Not everyone drives...Most will like the fact they can drive to the LCBO now.
Some illegal producers could possibly go legit but if the LCBO thinks they can charge double the current price for weed, they will simply fuel the black market. Just like they've done by taxing cigarettes.I get where the you are going. But you forget the inherent laziness of people. And probably a bit more for the average smoker. They won't grow it themselves anymore than the average drinker brews his own.
Soon the stories will begin exholing the virtues of commercial grown pot vs bad old illegal pot. Medical stories, crime stories etc. There will be slick beer commercial style marketing campaigns. And there will be a crackdown on the illegal growers.
Many of the large illegal growers will go legit if they are able to. So you will find illegal supplies dwindling. Remember it's easy to find because we are a major producer. So if they choose to go legit (and many will) then the LCBO becomes the pipeline.
The only place you will be able to get it in the long run will be either the California model as you mentioned for home growers, The LCBO, and the Native reserves.
That's my prediction for about 5-10 years after this is done.