Just Apple being cheap simple as that, there's sub $300 notebooks with better wear & tear resistance to KB use. I bought the cheapest 2in1 so I could to learn W10, 6 years on the KB still looks like new as does a heavily used Acer Switch 5 which was $600. The far more expensive Apple notebooks past 2012 keys have all polished up in a matter of months. M1 MBP I'll see but it's not used much.
My 11-year-old MBP proves Apple solved this issue over a decade back as that's been absolutely hammered both professionally & privately (engineering & gaming). Apple now either uses cheaper materials to save cost or to tip the users to update more frequently. Either ways not a good look from a so-called premium provider.
Really poor show in my book, premium is supposed to be a better product. Jobs was many things and not all good but he understood the value of the customer. Apple today just wants easy money...
I used to buy highest spec, these days I buy the lowest spec I can get by with as Apple is far too much about itself these days...
Q-6