I fell off your train of thought about halfway through, but I agree with the main point that there's way too much unnecessary churn in the web dev world, 90% is about right. Just busy work, changing APIs, forcing new and untested paradigms onto library users, major version upgrades that expect everyone to rewrite their code..

Intentionally or unconsciously, much of the work is about ensuring there will always be demand for more work. Or else there's a risk of naturally falling apart over time. Why would you build it that way!?