macbook pro keyboard keys look polished after a few months
All keyboards by any manfacturer have shown wear over time.
We even had keyboards made with stainless steel designed for heavy use and they showed signs of wear.
Fingers carry dirt which abrades the keys and coatings over time - even if you wash your hands prior to use , you pick up something from the desk and back to dirty.
My macbook pro keyboard I have worn through to the clear plastic past the symbols and black base.
Replace the keyboard and put a cover on it but nothing lasts forever. Or use an external keyboard but not practical in all situations.
You are not alone...