DC legalized in 2014, but the house republicans have added language preventing the DC government from spending any money implementing a licensing program for the last decade:

https://thehill.com/policy/finance/210566-house-gop-blocks-d...

I don’t use it so this isn’t directly relevant to me but I’d been looking forward to some Colorado-style boosts of tax revenue other than my property taxes.

Pull almost* any thread, when the question is "why haven't we made more progress", and you'll find the same answer