They probably won't do the same on PC, cuz yeah, somebody would break that near instantly.
I'm not an expert and won't claim to be one, but I think if people can break denuvo by spoofing the phone home, they could break any such similar phone home or online activation/requirement just as easy.
As others have pointed out, it's really something Valve should be looking into rather than individual publishers. Some ideas posted already would probably work out quite a bit better than what we have currently. Such as leaving out the .exe, randomly encrypting only 10% of the files, leaving out other small files, etc...