Here are some long-term predictions: The federal government will not legalize without a tax plan. The federal tax will not be ad valorem (percentage) at retail (look at tobacco and alcohol). Federal legalization will come faster if there are significant state experiments (taxing product weight or THC) that make Congress feel comfortable that it knows how to tax cannabis.
So state ad valorem taxes may be an impediment to federal legalization. A small one. Non-ad valorem tax experiments (as in New York and New Jersey and several other states) might be helping.
But most marijuana-legalizing are states using ad valorem taxes. The tax experts left and right say not to. https://newrevenue.org/2021/09/01/ad-valorem-excise-taxes-are-not-the-way-to-go-for-marijuana/; https://itep.org/taxing-cannabis/; https://taxfoundation.org/safe-banking-act-state-marijuana-revenues/
Are retail taxes just easier to collect, and ad valorem lends itself readily to retail collection?
No legalization without taxation seems a safe bet. At least at first, it would be better, I think, to just keep the 280E selling expense tax and NOT add a federal excise tax, but how many votes would that get?
The Center for New Revenue 