This has been going on for decades. I remember back in the 70s coming across a wild pot farm in the cascades on a late summer recon for hunting season. When we realized where we were, we beat feet outta there.

I also recall my uncle telling me about farmers growing it in the corn fields.

That wildweed flower, it grows anywhere!!!

I think it is far too late for legalization to make any difference where it is being grown illegally, whether on public or private land. Even if the feds changed the posession/use legalities, you can be darned sure it would still be heavily regulated. There's still a lotta folks making 'shine these days, despite the fact that booze is legal to drink, but not legal to make for distribution unless you are licensed.