But if that's what you go by, then how about this: there are other SRDs which have yet to be released into the CC, and for people who still publish under the OGL, the continuing anxiety about that is a "negative impact" by your standard.
No, it really didn't. Just ask anyone who publishes under the OGL for a different SRD. Or do they not count?
And at the end of the day, I'd say you're wrong. But don't take my word for it, take the word of this
PhD dissertation about how the OGL resulted in more creativity, which means that damaging it the way WotC has is likely to result in less, since the CC doesn't have as many SRDs.