Next time, try reading the whole thread before jumping in: it was Huck Finn who said "making SLR lenses in RF mount" (or vice versa) as if it's impossible, worthless or never been done. 🙄
Then, go look up Leica's 90/2.8 2nd version (R and M), the current 50/2 (R and M), the 1st and 2nd versions 135/2.8 (R and M), to name just four.