>But it was used as a selling point.
Yes. That's pretty much what I said. A lot of those using it as a selling point didn't actually care that much about the benefits to the state of a new taxation stream.
That said, I'm willing to believe that a lot of people assumed that people were willing to pay a lot more to go with a vetted legal source (or would only go with a vetted legal source) than has, in fact turned out to be the case.
There's at least some evidence I've read that suggests legalization hasn't led to a lot of increased use. If that's the case, it's reasonable to assume a lot of users already knew how to acquire pot in the black market and don't see a lot of reason to start spending more to go legal.