I'm in Massachusetts, where recreational marijuana became legal in 2016. The day after it passed, you were legally allowed to grow on your property and smoke/partake in the privacy of your home. No driving, no possession while driving, no use as a passenger in the car, no buying from illegal sources. Other than that, it has been a sloooow process. Two years later, we still do not have recreational shops, though we are getting closer to the business permits finally going through.
The other thing is there are A LOT of people who smoke pot in this world-people from all walks of life, people you wouldn't expect, and people who have been partaking for years. It's quite normal, legal or not. I don't expect a large spike in new users once the recreational shops open up. I think it's just going to make those who already smoke, an easier and more interesting experience.