The normal business model for free to play games is that a small number of people pay a lot of money for cosmetics or convenience, this finances the game and is how the company makes its money. The free players then provide value by being there making the game feel alive and being someone, the spenders can show off their cool items to.

That is how monetization for free to play games have worked for a very long time now. Changing that without letting people know up front is absolutely a betrayal of trust.

I would hazard a guess that the vast majority of the people playing Pokemon Go have never even considered the question.

This is disingenuous. They charge for gems and this model is well understood to make a fortune without selling user data at all

It might even go further than that - I'd say the typical person is more suspicious of free open-source software than the typical "IT professional".

Almost nobody would care about this issue even if they knew it was being done.