"WE KNOW" automatic copy will destroy à previous version, WE just forget... You can create à simple snippet that, on compilation, copies the saved version with a different name, maybe even a timestamp.
Yes you are right.. in fact we forget.. I think the reason (at least in my case) is because in the past, programming, drawing and designing (photoshop, MS Paint, AutoCAD... etc) prompts
for saving, but document editing (MS Word..etc) are auto-saved by default.. so instead of writing a new code for each application, I think it's better that this feature is not the default, and it can be an option for the user to enable it if he wish, (instead of disabling it.)