> Java replaced this implementation in 1997

If that date's correct, they replaced it with another flawed implementation. The 'good' one came much later: https://jcp.org/en/jsr/detail?id=310

> What are the forces at work here?

I feel like I'm always simultaneously engaged in about 5 HN threads at a time, advocating for some combination of immutability, type-safety, and/or no-nulls. It's basically all I do.

By and large, people simply aren't into it. "Because the world is shared and mutable" is a pretty common rebuttal:

4 hours ago: https://news.ycombinator.com/item?id=42876487

2 days ago: https://news.ycombinator.com/item?id=42850569