Windows 95 changed that, and so one of the compatibility shims it got is that the allocator had a 3.x adjacent mode, which would be turned on when running SimCity (and probably other similarly misbehaving software as well).
Nowadays this is formalised in the compatibility engine (dating back to windows do), which can enable special modes or compatibility shims for applications (windows admins trying to run legacy or unmaintained applications can manage the application of compatibility modes via the “compatibility administrator”).
It was a very different world back then. You couldn't even assume a dial-up connection.
Nowadays, the software would have been automatically updated for 99% of the machines running it, whether they wanted that update or not.