Washington is a state that has looked the other way on marijuana my entire life. There were head shops 50 years ago when I was a teenager. We have had legal medical marijuana for nearly 25 years.
There is simply so much marijuana available and so many people are growing it themselves without any fear of prosecution that they just expect it to be legal. My guess is that the people making big bucks will see this as a threat to some of their ill-gotten gain and keep growing at home illegal if they can.
I am sure that you realize that Alaska has allowed people to grow their own since 1975. This lowered the profitability to the point that no one bothered to push for legalizing sales until 2014.
https://www.washingtonpost.com/news/wonk/wp/2014/09/24/alaska-legalized-weed-39-years-ago-wait-what/
You don't need much space or expensive equipment to grow marijuana.
Yeah, I’m in Oregon. *eyeroll*. I can remember when laws were deterrents. Fifty years ago there was a headshop in the back of a waterbed store in the adjoining town. And once, there was a pathetic little marijuana plant growing in the window of a candle shop. As kids, we went and sneaked a peek at it. Now, it seems there’s a “glass store” on every other corner. Never thought I’d see a $5K bong.