Hearing aids allow you - rather enable you - to listen again. Without them your understanding and comprehension gets lazy.

Imagine if you stopped playing basketball because of a bad knee.

Then years later you get a knee brace and are able to play again.

How long, and how much practice would you need before you could play at the level you were at before the knee problem?

And without properly fixing the problem (just using a mobility aid) could you ever return to pre-knee problem levels?