The term "loot box" has, since I want to say the early 2010s, referred to the mechanic described in the quote. It's hard for me to say what the earliest games were to create this mechanic, especially since its origin seems not to be in the traditional Western games but in East Asian games.

The model is very strongly associated with the rise of "live service" gaming, with Overwatch and Battlefield being some of the more notorious offenders.

I was under the impression Eastern games preferred the loan word 'gacha'.