It is because we did not have a plan for removing deprecates features. Deprecation in documentation only helps third-party code. Instead of adding a complex code which switches between using old and new names depending on Python version, the third-party code can continue to use old names without worring about deprecation warnings, and switch completely to using new features only when support of old Python versions be dropped. 3.7 and 3.8 are not so old and may be still supported in third-party code.

I have created a PR which adds deprecation warnings, but I am not sure that it is worth to include it in 3.11.