You're confusing quite a few things together.

The basic peripherals (keyboard and monitor) of today still present the same interface as they did back in the IBM PC era. Everything else is due to massive hardware expansion, not hardware churn.

How often do you update your drivers compare to your typical internet connected app? Software that handles the idiosyncrasies of the hardware (aka drivers) generally has a much longer lifespan than most other software; I don't see how you can reasonably say hardware breaking backwards compatibility is why software keeps changing.