Interesting that the web ecosystem basically works on the ivory tower model. Roughly every 2 years there's some new ivory tower and a lot of greenfield projects move to that. Brownfield projects become legacy and go into maintenance mode or get rewritten after some number of years.

I've seen something like this:

- Delphi desktop app (some time in the 2000s)

- Adobe Flash web app (in late 2000s to mid 2010s)

- 2015-era JS framework web app (mid 2010s to present, considered legacy codebase now, no feature development)

- 2020-era JS framework web app (late 2010s to present)

I expect another major rewrite or move to a new project in the next ~5 years

Depends where you look into, I have been pretty much Java and .NET since 2005 in what concerns Web development and backend infrastructure in distributed systems.

The web frontend works that way because little depends on the frontend. But the infrastructure one layer down is obsessive about backwards compatibility, both in the browser and in HTTP servers. JavaScript frameworks change all the time, but nginx and apache and friends have lasted for many decades, for good reason.