I was also wondering what businesses would do well in an already saturated market of tourist rentals, tourism activities, cafe's and restaurants in places like El Bolson, San Martin, Villa Angostura etc... Do you really think an Asian restaurant/cafe would do well in SMA...? It had crossed my mind....are there any Indian places?
If I am frank, then I would say probably no, but it depends on pricing, food and location.
I would at any good Asian restaurant at least once a week, but SMA is not BsAs. Most people here never eat spicy and and only go out to eat pizza. The tourists only come to eat steak and maybe some trout. Then again, it depends on the cooks and pricing. I was amazed that a nearby new pizza place is doing great. It is a few blocks away from the main area, so nobody passes it unless going there, there are dozens of better-located pizza places in town. It is the 3rd restaurant in the building in 3 years, but the first 2 were always depressingly empty. This one serves 'just' pizza, but from a wood oven and for good prices and with fast and friendly service and is full every night. So location alone is not the holy grail, nor a big problem.
There is a chinese restaurant (tenedor libre) since a year, but for me it is too 'Argentinean' too be tasty, i.e. too salty and too fried and no spices. There are a few places with Sushi, one super expensive, another more affordable and quite good and some mediocre ones.
We do cook Asian for friends sometimes and most love it, but people are simply not used to it and I am not sure if they would go out to eat it as much as we would. People love specials and good deals, so a lot comes down to good marketing. Note that most restaurants in SMA offer 10-20% discount for locals, which is nice.