The answer to almost all of these if we're answering honestly is that we don't know. We have no idea because Bitcoin is not a centralized system and that's a good thing. We want people to make decisions based on their own values and profit calculations, and not on centralized dictates.

We have incentive guidelines based on economics. We know lowering the price means more people buy. We know that friction and bad user experience prevent people from adoption. But ultimately, playing with incentives to try to get a particular result is technocratic hubris. Particularly for the reason you point out. We really don't know what the second and third order effects will be. This is the main failure of central planning.

That said, I think the way to solve this is more decentralization. We should be encouraging nodes to be more self-sovereign and decide for themselves what they relay and encourage hashers to decide for themselves what they mine. Power to the people, I say.