For example, I used Sketch on my ond mac once and was quite happy, but then they dropped support for the OS version that mac was stuck upon. And since newer libraries resources etc all target latest version of Sketch, the version of Sketch I could run quickly became useless.
However, it's great that developers are not too concerned with backwards compatibility. It was really holding back a lot of software
On your second point, proper developers release security updates and backports for software released decades ago, while others always chase new shiny things and contribute a lot to this unsupportable legacy hell that we have to deal with.
That's one thing Windows is generally much better at.