Anecdotal evidence.
> needless to say many treatment centers are based in cities and visited by what you might call a more educated and worldly crowd
Appeal to authority.
How about some actual scientific evidence? I'm no expert on the matter, but from what I can find on Wikipedia[0], the benefits of Ayurvedic medicne were inconclusive at best.
As someone who has spent time in medical research, I will admit my opinion is skewed. I've worked with plenty of researchers from India, and none of them have given any credence to Ayurvedic medicine. These are people who (like any researchers) will use any and all means available to them to come up with scientifically viable theories that they can use to get grants. If Ayurveda were as great as you claim it is, then they would have definitely given it a shot.
0: http://en.wikipedia.org/wiki/Ayurvedic_medicine#Scientific_a...