Games from the 2010s are still "new". There are several major game series where the most current entry came from the 2010s. Think Skyrim & GTA5.

Game companies still have the source code an tooling sitting around. With some minor texture brushups, they can release a "remastered" version and get $20 out of people again.

Nintendo games are the odd ones here, because their love of novel gameplay means that a lot of first party games need to run on OG hardware for the full experience. Think Wii, DS/3DS.