Bomberman shrank the arena when the matches went to sudden death. Pretty sure others also did this (certainly common in single player games of that era and earlier - arguably Joust with it's rising lava is close to being the first for that sort of thing)

lookup H1Z1

also this concept was a minecraft mod called hunger games before that even

PUBG succeeded and vastly popularized the BR genre but it definitely didn't invent it

https://en.wikipedia.org/wiki/Battle_royale_game#Early_games...

  While Battlegrounds was not the first battle royale game, its release to early access in March 2017 drew a great deal of attention, selling over twenty million units by the end of the year,[18][19] and is considered the defining game of the genre.

Like almost all game mechanics, I'm fairly sure I saw this in a WC3 custom map half a decade ago.