Depending on the state, plants need to be tracked from seed to sale. That is just one aspect of it that I'm familiar with. I'm sure the compliance burdens beyond that are significant.

A combination of federal illegality (which affects banking heavily) and special compliance requirements necessitates custom industry solutions AFAIK.

But that's really no different from discrete manufacturing, where you have to track precious metals, hazardous materials, import/export regulations, etc. I wonder why the major players don't just make the minor adaptations so they can serve this market, too.

Likely federal law. Its not settled legally if providing services to recreational dispensaries can implicate your company in felony drug distribution. Its unlikely, but a risk. It may even cause issues with the bushiness main product. Things like insurance liability shifts and the like.

No "big name" company has wanted to test the waters.

Not that familiar with it, but part of the issue is that financial institutions above a certain size won't do business with them because it's still illegal at the federal level and they're afraid of the ambiguity. I wouldn't be surprised if that affected what PoS software they could use.

Large financial institutions still dont play nicely with internet porn, which really isnt that ambiguous legally. I think a lot of it is PR as well. They dont want to be associated with moraly ambiguous industries

A lot of this is a consequence of the George W Bush presidency, where the DoJ was encouraged to crack down on pornography using obscenity laws. From the histories I've read, one of the levers they used was informal pressure on financing institutions that served the distributors.

https://en.wikipedia.org/wiki/Obscenity_Prosecution_Task_For...

I place the blame squarely on the Obama Justice Department's Operation Choke Point. The previous task force was at least targeted towards specific, named, businesses and brought them before a court--not a blanket, de-facto ban caused by threatening financial institutions, directly.

https://en.wikipedia.org/wiki/Operation_Choke_Point