Having experience in both worlds, I can assure you medicine isn't what you seem to think it is. Social status, and income aren't so grand these days, and working conditions are bad for a lot of practitioners. And "debugging meat machines" is anything but well-understood in the majority of serious cases.
I know working with Javascript can be an annoying proposition. I'm maintaining a web app I wrote a couple of years ago in vanilla JS and gotten to be kind of a hairy beast. Probably would be better to rewrite it, but it works and for all the warts at least I know where they are. Maybe I'm just too lazy to take the time and effort to recreate from scratch. I figure by the time I got it working, I'd always be lagging the newer, "better" stuff anyway.
Interestingly, your comments about education have a parallel in CME (continuing medical education). There are real paradigm switches that appear from time to time, but not as much as you'd think. Most changes have to do with small refinements like new medicines that are variations on the current ones, theoretical or research findings, administrative or procedural issues.
So yeah, the really important information approximates the 5% figure you cite, and a significant amount of "updated" info is only marginally different or new, more or less equivalent to the "newer, hotter stack" idea you mention. Sure seems all that greener grass still needs to be mowed about the same way.