Windows 95 had special code just to fix a bug in the original SimCity
It's easy to take backwards compatibility for granted on PC, so much so that we rarely even use the phrase "backwards compatibility". Most old games will simply run, and for everything else there's usually a compatibility mode built into Windows or DOSBox to get it going.
This didn't happen by accident, as an old blog post by a former Microsoft programmer explains. When Microsoft wanted users to switch to Windows 95, for example, they went so far as to add specific code that looked for SimCity and, if it was running, changed how memory allocation worked so that the game wouldn't crash.