Cloud's got nothing to do with it. The thought of standing up a windows box to serve anything other than profiles and user surveillance is simply foreign. Budget webhosting has been a thing for a long time and standing up a *nix VM is also no big deal. In 25 years in industry I never once saw an IIS server used in the wild. shrug
I'm surprised by this, maybe its industry specific.
An 80:20 split of windows server to everything else has been pretty common in the areas I've worked both as a <10 day contactor and as a FTE.