MACs will, obviously, do everything that most folks 'need' to do, but PCs are, as Dick says, less expensive and more 'familar'. If logic prevailed, EVERYONE would use MACs, and all interesting programs would be re-written for MACs...but some things just do not exist for them.
...and, it may be like the difference between automatic & stick shift cars.....some just prefer the tinkering and tweaking that goes with PCs.