That’s true, but the cell towers are probably going to be of a similiar cost in India vs US. Lower (because wages are lower) but similar because the actual equipment is going to be the same price.
PPP is only relevent for things that have different prices in different countries (housing, food, etc). There are many things that cost roughly the same wherever you are: oil, macbooks, cell towers, etc.
As a general rule, the easier something is to arbitrage, the less PPP matters. The cost of arbitrage includes transport costs, taxes, and depreciation schedules (vegetables would be cheaper in India vs US because they are hard to transport, for example).
Of course this is only relevent if the US companies aren’t making crazy margins (I don’t personally know, but I suspect it’s possible).