Untrue. Pliny moralized writing about how much the Empire lost in the oriental trade, much more interesting text from this time the Periplus of Maris Erythraei. One of those luxory good was quite popular among southern indian elites, it was called wine...
Can the Romans afford to just abandon Britian? Seems like the blow to imperial prestige would be immense. It would be the first major withdrawal from a province - a sign of major weakness, imo.
Wealth isn't everything in this equation. Mesopotamia is hard to defend from the east and war and even the rumor of war can naturally disrupt trade.
I think Mesopotamia, if taken and held, is something of a last gasp of imperial conquest. The resources that will go into holding and defending it make it less of a beachhead and more of a fortress. Over the next two hundred years or so the Roman army is going to become increasingly defensive in it's outlook and doctrines. There's going to be periods of upheval and civil war and plague down the line. Cash infusion won't fix either of those things - at best you're kicking the can down the road.
Mesopotamia is a sink. It's not a money sink - obviously it'll be profitable - it's a manpower sink, a time and attention sink, a logistical sink. It's Roman Emperors investing huge amounts of effort and capacity no matter what the outcome.
Can the Romans afford to just abandon Britian? Seems like the blow to imperial prestige would be immense. It would be the first major withdrawal from a province - a sign of major weakness, imo.
Wealth isn't everything in this equation. Mesopotamia is hard to defend from the east and war and even the rumor of war can naturally disrupt trade.
I think Mesopotamia, if taken and held, is something of a last gasp of imperial conquest. The resources that will go into holding and defending it make it less of a beachhead and more of a fortress. Over the next two hundred years or so the Roman army is going to become increasingly defensive in it's outlook and doctrines. There's going to be periods of upheval and civil war and plague down the line. Cash infusion won't fix either of those things - at best you're kicking the can down the road.
Mesopotamia is a sink. It's not a money sink - obviously it'll be profitable - it's a manpower sink, a time and attention sink, a logistical sink. It's Roman Emperors investing huge amounts of effort and capacity no matter what the outcome.
My point is more that the benefits of Mesopotamia are essentially based on taxation and larger overall population. Defending and administering that population, let alone further expansion, takes immense investment.
The best aspect of defending Mesopotamia is the chance of indigenous revolt is rather low, I expect. The worst is that Persia and the Arabian interior will both be difficult to defend against in the long term. Both are almost impossible for the Romans to conquer and both will necessitate the establishment of federates and major garrisons.
Roman attention will be drawn Eastward. I think you make a good point that more ventures will be attempted in this scenario. The question is where they go and how likely they are to fail.
I disagree that Mesopotamia makes an offensive strategy in Germania more likely or more useful. I think it makes Emperors more likely to spend more time out east and less likely to focus on Germany and more likely to have fewer resources to conquer Germany and more money to buy off tribes rather than pursuing long term solutions.
Holding a hypothetical line that deep into Europe would be expensive as all hell with premodern logistics.
Edit: I also recognize I've had this debate with roughly the same parameters many times. My general opinion is that Rome stopped where it did, more or less, for good reasons, mostly relating to logistics. If the Romans had been able to keep going they would have - they were nothing if not boundlessly stubborn and persistent. Those reasons are extremely hard to overcome, I believe. And I think I'll leave it there, since otherwise I'm just being a naysayer and getting in the way of creative ideas.
Why would this impede Romanization? India had a different set of cultures separate from that of Mesopotamia, Persia, or Rome, so I am not sure how contact with India is relevant. Wealthy Syrian traders back in this era were often already Hellenized. The vernacular language of Mesopotamia at this time was Aramaic, not Parthian, and Greeks had already been present as urban mercantile classes for many years by the time of Trajan. The Parthians themselves used the Greek language alongside Parthian.On the other hand, had the Romans successfully held the ground they would have found it difficult (if not impossible) to Romanize the province. The rivers’ flow into the Persian Gulf would have ensured constant contact with India.
Syrian merchants (who some historians argue dominated Roman trade within the empire) would have quickly expanded their efforts through the gulf and flooded the Roman market with Eastern (desirable) goods. The flow of this trade would have ensured a constant flow of Eastern culture into a province that was already, by sheer distance, less swayed by Roman influence.
Are we then looking at a Hadrian's Wall across the Georgian mountains in the Caucasus?
How easy in this period is it to defend Mesopotamia from attack from the East? What are the natural defensive boundaries?
Maybe if the Roman's abandon Britain and send 3-4 legions instead to garrison and defend Mesopotamia?
Maybe the Roman's could build a series of forts, entrenchments, towers, maybe even trenches(to defend against Persian heavy cavalry).
Holding Mesopotamia as a desert is a way better trade-off than having it prosper under the hands of a rival eastern empire.It doesn't hence why local dynasties over the ages have often been nomad warlords or their descendants. There are no natural chokes, cliffs, mountains or anything except the river valleys, the marshes by the rivers in the south, and stretches of desert on both sides not too distant for invaders to cross (unlike Egypt), not to compact enough to sufficiently patrol or garrison and too vast to fortify.
The area is fertile with nothing else as resources, it isn't self-sufficient nor are its rivers easily navigable; it relies on the North and East for stone, wood, and metals. Southern Mesopotamia receives virtually no rainfall forcing it to rely on vast irrigation works easily disrupted by chaos and war. The region needs trade which requires the Romans to secure the North/East or build railroads to the Levant, no trade=no way to acquire wealth in the form of gold/silk, the few goods that are compact enough to justify a caravan back to the Mediterranean. The Romans need to conquer a lot, they also need to adapt for warfare against mounted nomads in an open desert, and they need some way to communicate quickly with Mesopotamia or it will over time become semi-autonomous.
Holding Mesopotamia as a desert is a way better trade-off than having it prosper under the hands of a rival eastern empire.
It's not just any desert, though, but the highly fertile Mesopotamia. All the Romans need to control is the two rivers and a few cities between them. They'd already settled more arid lands in Arabia Petraea and North Africa.As a Professional Cactus I can testify to the idea that not everything should be done, even if they can be. Taking desert is fine and all, but keeping it is nearly impossible; the Romans are no exception, come the next time of troubles and the Middle East will change ownership again.