It is true that they generally lacked the imagination and faith to undertake such projects, even though it would pay for itself fairly quickly.
One would want to know why, if something like that would pay for itself so quickly, it wasn't attempted.
Heck, we even see the OTL transshipment canal abandoned in time.
Saying that it was "a lack of imagination and faith' across the centuries from ~100 AD to the mid 19th century (and multiple polities) just doesn't make sense.