The incentive for miners after the coin subsidy runs out is transaction fees. So long as the net sum of the tx fees can subsidize enough hashpower to keep the network "secure enough", Bitcoin will be fine. The gradual decline of subsidies over time is meant to make this transition as graceful as possible.

I don't see anybody in the Bitcoin community being ok with moving to PoS or removing the hard cap, that question has been "asked and answered" as far as BTC is concerned. PoW is a more equitable system for initial coin distribution and long-term control of the network as energy is the most equitably distributed resource on earth to base a currency on. Unlike previous methods like precious metals or stable governments. PoS inevitably trends towards centralization, it's just the nature of how that system works. Bitcoin has chosen decentralization at every other opportunity, I'm not sure why it would it would change course.