The cost of living in India being much lower than the US, what prevents people from engaging in medical tourism for prescription drugs combined with a nice trip

The cost of living in India being much lower than the US, what prevents people from engaging in medical tourism for prescription drugs combined with a nice trip abroad? I think ultimately this is what will keep caps on the price that can be charged -- if your treatment plan costs you $1,800/month, and a return airfare from the U.S. East Cost to Delhi is $600 return on a budget, I'm surprised people are not booking trips right now.