Re: "Of course, being able to do your own support is a feature, not a bug. "
More so if you're an SMB and you really have no way to be your "first line of support".
Most companies need software that 1) [mostly] work 2) have professional support when needed.
I have worked in environments where we had support from H/W & S/W for servers from HP & IBM in big iron territory and from industry-specific package vendors but commodity H/W & S/W generally means 1st line support from a local dealer or a freelancer; how many SMBs are able to get first line support from Microsoft?
Why should you think a local dealer or freelancer can support Windows more professionally than they could support Linux if they chose to do so? And, as has been said elsewhere, you can get support contracts from Red Hat, SUSE and Cannonical for their distros.