Well, competitors have existed since a decade ago, but many have also died. The closest competitor now seems to be Plesk, but it hasn't been able to snatch the crown from cPanel yet. If I remember it, Plesk 7 or 8 for Windows is a mess. All software suck :)
It seems the biggest issue is that cpanel/plesk makes it easy for non-system administrators to setup a web hosting company. I don't think a cpanel competitor could solve that problem.
that's exactly it! It makes running a hosting company an easy, point and click affair -- and that is somewhat the point I am trying to make.