For some reason, this hasn't happened yet, and the time frame that has passed since the "loss" (e.g. from ~2010 on) is comparable to the time frame the UI patterns were originally introduced (e.g. Windows 1.0 to Windows 95).
I'm afraid the prevalence of touch-screen use and the lack of focus on power users by UX designers is making the degradation permanent.
No. Every creation and discovery is influenced by culture and individuals.
Even if you assume the same level of skill and effort will be used (it won’t) there are still many paths and forks to take.
Consider that most “ui designers” come from graphic design or psychology backgrounds, while 90s UI was designed by engineers. Those groups have different values and make different decisions.
I'm afraid the prevalence of touch-screen use and the lack of focus on power users by UX designers is making the degradation permanent.