> There is no formal deprecation or EOL process

Yes there is or we'd have been talking about std::auto_ptr as well.

> New features rarely undermine or reinvent the older ones.

Many languages have mistakes they've later tried to sweep under the rug. JavaScript arrow functions trying to convince everyone that bind(this) wasn't ever a thing, for example.

C++, for whatever reason, is consistently the only language where people are determined to always dig up the skeletons and pretend they are at all still relevant. It's not unique in having skeletons. It's not unique in having language spec mistakes that can't realistically be changed, just ammended with a newer, better alternative.

But like the saying goes, there are only two kinds of languages: the ones people complain about and the ones nobody uses