I'll agree with Caliban that this has been said before, and they still need to change the DMG language, because it absolutely contradicts what's written there.
The problem has never been that they're prerequisites (a bit of a straw man argument). The problem is that, while not being prerequisites, they are "a minimum on the caster's level".
Furthermore, I'll note again the further problem wherein Andy's last statement (in the link) is "Of course, the DM might also adjust the creation costs accordingly.", with absolutely no rules to guide what kind of price adjustments are expected.
But yeah, if Andy's saying it then the rule may well be changed in the new version.