Haha, there's still things embedded deep in code and in CPUs that go way back to the 80s. If only y'all knew. It's all shit built on top of older shit, built on top of even older shit with kludges and hacks to glue it all together. Know why Windows has five different ways to access the same setting? Because if they get rid of the older methods, they break a ton of other shit that depends on it too. A house of cards or a Jenga tower.
A modern PC can STILL natively boot a DOS floppy from 1986 in legacy BIOS mode because of this.
Theres also examples in the corporate world where some companies are STILL running 70s mainframes, and use shiny new PCs as front end terminals that just connect to the same old backend.