You want to legally mandate backwards compatibility? That would cause all kinds of unintended consequences.

The ability to break backwards compatibility has been central to the continued development of every platform. Windows, Mac OS, Android, iOS, the web, are all unable to run certain old programs. Some of these platforms offer more compatibility than others, but none offer 100%.

Most of the time, the breaking changes end up being good for consumers, especially in the long run. Change is necessary for technological progress and banning such activity would be like throwing out the baby with the bath water.