Forgive the naive question, but my recollection from the days of 386s and 486s is that the main hurdle to running Linux back then in a 386 or 486 system was RAM. The typical 386 system did not have enough RAM to properly run Linux. So has Linux become slimmer in the ensuing quarter-century?
Foundations used to solicit the donation of old computers. I was considering such a donation and asked the obvious question. It turned out that the desktop box I was considering to donate was not powerful enough to donate to them. Then I did a double take, because the most powerful computer in the house also was not powerful enough to donate! This is part of the "naive" in my question.