[murgindrag]

Seen locally, all improvements are useful. PHP is better each year.

Seen globally, it's 10% improvement and 90% churn. One "improvement" is a half-fix, another is another half-fix, and so on, where after 5 improvements you're 97% of the way there.

In the meantime, you've broken backwards-compatibility five times, perhaps not always in the literal sense (old code still runs), but in the practical sense (old code has to be rewritten to follow modern conventions and be compatible with new code).

You've also had five learning curves.

And you have a ton of legacy stuff to support, from each of those five changes, leading to an almost unbounded explosion of complexity.