Today I learned! Though, what were the other benefits that the Silk Way was providing? I would have just assumed resources/intelligence.
Well, resources are vital when you go for military conquest, after all.
Roads and cultural (which includes military tought and organisation) exchanges played an important role too.
For the first, we can see how important they were with Alexander's campaign in Central Asia. It's simply easier and quicker to have armies using "marked" trails with more easily managable logistics.
For the rest...Giving our discussion about elephantry, being more accustomed and integrating local strategy and military tought is usually a good idea.
Alas poor Greeks. So much for the idea of Hoplite Invincibility!

Went to a fantastic lecture about the topic, and how utterly easy it was to disprove. And how tied it was to the idea of the Persian Immortals. Fantastic stuff.
I'd have tought
Kardaka being closer to hoplitic forces, tough.
This probably makes the point I wasn't straight with. Without Elephants they can't succeed, and the Greeks can't Elephant.
Well, they could and they did (up to revolutionnary development as howdah).
It just took time, and it may have more to do with prestige than real tactical efficience*, contrary to India, as they were relatively few territories were elephants were native.
You can see that Persian elephantry, while impressing Greeks, didn't played a real tactical role, probably due to their fairly limited numbers.
*Altough you have the Battle of Ipsos, where Selucos used 500 war elephants graciously sent by the Maurya Empire. But there again, the lack of native elephants made a large use a bit utopic.
Having Alexander integrating immediatly an elephantry from the recently defeated Indus Kingdom (that have then a limited number of "units"), is however stretching it.
My issue is more that you did it pre-emptively.
Maybe. My point is just that I'd want us to have a quality discussion without something that pops up regularily, and against which there's hardly rational discussion to have (once someone is convinced that X civilisation is superior to Y, not only that becomes a whole different question than Alexander possibilities in India, but you'd never break this with rational arguments, because that's not an informed or rational assessment).
That said, I'll end with this as well, to not derail the thread.
Anyway, moving on. I think we've shown that it isn't as easy as Alexander marching in and "VICTORY". Assuming that he has Memnons reinforcements, what would Alexanders likely response be?
Before going for Nanda Empire, he would have to deal with other small states, as in Gurjarat (Saurashtra among them?) and choose between going for highlands, desert or marsh, while Nanda army is going to wait for him.
I know he was one of the few generals to achieve victory on the steppe - but could be he be strategically flexible enough to find a counter to the sheer number of Elephants?
Well, he could. I don't think that's really likely, but he could.
But could his men take it? IOTL, it was the battle with Poros that made them unwilling to continue : assuming they doesn't mutinate then, are still they going to be much obedient with an elephantry taken up to eleven charging at them?
Even if they win, Alexander's gonna have troubles keeping up with them.
You'd have to defeat them strategically, rather than tactically.
I think that's the main problem. Alexander had no clue at all about India : its geopolitics, wealth, situation, military...
In order to have some strategic tought, you need something more than the king you just defeated saying "these guys stinks. Also they're a fuckton more powerful than I".
And giving that India was a big unknown for Alexander, even with tactical victories, I think he'd have bogged down while the rest of his Empire will contemplate some reedition of what happened in Greece while he was fighting in Central Asia.
While I think a longer-living Alexandrine Empire *may* do something about it (while I'd be more convinced by seeing it recentering on Near-East and Mediterranean basin), I don't think the conflated raid of 326 may have been that pushed.