https://en.wikipedia.org/wiki/Loudness_war
Edit: Regarding the infamous Vapor Trails sound debacle:
THAT is an interesting rabbit hole. It's not that it's mastered hot, exactly. Bear with me here - I think they were trying something very ambitious, but failed. So the Jesus and Mary Chain album "Honey's Dead" basically sounds like compressed shit - until you crank it, on a system that can actually reveal this stuff (it's taken me 30 years to eventually, by increments, achieve this)(and the discovery itself was also literally a drunken turn-it-up accident) - then it is one of the best-sounding recordings I've ever heard. The various re-dos of VT (fan "remasters" that attempted to restore peaks with software, as well as the recent "remix" which they should damn not have done a new MIX FFS) sound "better" until you realize it doesn't touch the original master of VT when cranked. It's like that version is TRYING to pull off what the JAMC album does, and in fact almost makes it.
Of course, if they had hit the bulls-eye, it would still sound like shit on most systems, and everyone would still have not understood. But anyway.