RH is becoming "the standard" for small businesses looking for MS alternatives because many ISV's making vertical business apps for Linux ONLY support RH.
So, if small biz X runs anything other than RH, they won't get any support from the ISV. Therefore, small biz X will almost certainly likely run RH, because they don't want to pay more for the extra help needed to get ISV app Y running on Debian/SuSE/whatever.
Furthermore, even if they did pay the Linux expert to get it working, it wouldn't help them if they had non-Linux related problems with the app, if the ISV won't help unless they're running RH (which can be the case). So another reason to use RH; after all, they're interested in running a business, not making a IT fashion statement.
So point #1: for most small businesses, RH is the only logical Linux distro. All the Linux experts in the world won't change this. (Of course, if source is available, then other people could provide support & bug fixes.....but this generally isn't the case).
So the small biz now has a choice of running RH supported by RH or supported by someone else. You do have a valid point that others than RH can support RH. However, I suspect RH will increase RHAS sales; the vendor has a lot of built-in advantages.
In summary, I'll give you 1/3; I'll give you non-RH support, but you don't address Andrew's gripes about RH's growing dominance, and "the community" / "great unwashed Linux loudmouths" / whatevers inconsistent treatment of RH & its competitors.
Tony