There may be people in this category who still have a very stable income in addition to Bitcoin mining. Mining is for the realization of their ideals of decentralization, and even for the progress of the entire civilization. I have been in Bitcoin for too short a time, and I have not met such a pioneer. But I believe they exist, and I hope they exist.
These are what I would consider amateurs. There's always a negative stigma around that word for whatever reason, but I'm not intending to make it sound like they don't have a clue what they are doing. Its basically the entry point, and I would expect the more amateur miners to sell, and buy Bitcoin. Simply because they've likely got into Bitcoin mining with a hobbyist attitude. Of course, they want to make a profit, but they aren't expecting to make significant profits at least in the short term. Plus, because they have to pay off bills, and get their investment back they likely will have to sell their Bitcoin.
I would expect the more significant mining operations to be saving their Bitcoin for a rainier day. They almost certainly do exist, even if only partially i.e they sell a share of their Bitcoin mining profits, but are hoarding a significant portion of it.