Example: adding OOP in PHP and Javascript. In both examples, especially the first attempts, were half-baked. Why bolt on half a language feature? Both languages would be much better served with dependency management and / or modules, which for both languages came out of the community at first.
Counter-example would be Go, that resists change - especially if it's requested with a "this feature is in language X! I NEED it!". From the FAQ: https://golang.org/doc/faq#Why_doesnt_Go_have_feature_X (followed by some features other languages have. Generics / type arguments is one that will probably be added in an upcoming version of Go, but they only considered it once they fully understood the problem and need)