You can replace coal mines above with a million other things, I chose a dramatic, niche example.
The fact is that in recorded history, there have been almost no instances of economic setups without the downtrodden. I like efforts like UBI being made to address that, but it is important to address the fact that UBI itself is not the final solution. It is still possible that we reach a working solution eventually(who knows when?) by exploring things like UBI though. A lot of online discourse simply lies in a narrow band of "UBI = communism which didn't work in the specific instance of the soviet union" and on the other side "opposing UBI = oligarch".