That glosses over RedHat's strong arm sales tactics of the community, and rules-lawyering the GPL. Redistributing "their" source, as allowed by the GPL, is liable for your support license to not get renewed. And where's the Red Hat kernel source in a digestible format? I haven't followed recently, but they were at one point distributing their diffs to the mainline kernel as a single giant patch file and arguing that it was okay. It may abide by the letter of the GPL, but it's against the spirit of interoperability.
RedHat's the first billion dollar Linux company, but first and foremost it's a business. Their sales people are aggressive and their lawyer's hungry. Support contracts don't exactly fly off the shelves, especially when there's a huge community of experts.
How many people do you know that have given money to Canonical for Ubuntu?