Why dont windscreen repairs affect renewal prices & NCD?

I see it mentioned that having a windscreen replaced doesn't affect your renewal price or your no claims discount, why not?

Considering you get your price bumped up for any and all reasons this seems strange to me, especially considering a windscreen is anywhere from £200+ and installation is £200 as well?

Also why don't people have their windscreen replaced more often if you only have to pay £100 excess for a new one?