General purpose computers, as we understand them, are a niche market and potentially quite harmful in untrained hands. Apple is targeting the mainstream consumer. They still sell GPCs though, under the Mac brand.
Apple is welcome to build the "mainstream computer", but they should do so with respect to the protocols and open-source space around them. If they continue their oppressive approach to hardware and software development, they'll have a hard time defending themselves when people accuse them of a monopoly.