Im a newbie and have a question:
1) If the difficulty increases exponentially.
2) If in the coming months "halving" will reduce to half the miner's reward.
3) If the projections of various spreadsheets indicate that it is not currently profitable mining.
How will continue to operate the system?
Almost every user on this forum asking themselves the very same question mate. I believe there is no one who can actually give you an accurate answer. I personally think that bitcoin is strong enough for this challenge. I am not saying it will be easy but it will all be fine.
I agree, I think that we still have at least 3 to 10 halvings away from a point where we'd need to set up a solid fee market. But regardless I think that it'll happen naturally.
Miners aren't forced to run their operations, so in the end only the strong ones will survive.