> In one generation, smoking went from the coolest thing you could do to one of the least cool things you could do...that message was sent by banning smoking from public view
Being made illegal or banned only makes things cooler. Marijuana is cool now despite being illegal.
Attitudes toward tobacco changed because of the power of advertising. There's a certain justice in that, since advertising made it popular in the first place.
No one said anything about illegal. A ban on smoking in restaurants is not the same thing as making smoking illegal. You can still walk into any gas station and buy cigarettes, you can smoke them in your house and your car and on the sidewalk and in public parks and even right in front of a police officer.
My university banned smoking on campus years back, and no one said "aww man smoking is so cool now that I can't do it on campus". It's just so inconvenient to smoke now that fewer people bother to do so. It's not cool to have to put on your coat and walk three blocks to go have a smoke every hour.
All of that applies equally to marijuana. Yet the public image of one is improving while the other is declining, for reasons other than your explanation.
To be socially unacceptable, society has to agree that it's unacceptable. But the process works both ways, and something that was socially unacceptable can also become socially acceptable over time. Right now it seems society is rejecting the notion that marijuana is unacceptable, which is leading to it become more socially acceptable and more legally accessible. The realities of the drug seem to have failed to live up to the picture painted by anti-marijuana marketing and so the marketing failed.
For a long time being homosexual was illegal and socially unacceptable, but that has changed over the years after the expected social harm from homosexuality had not been realized. It's the same process, just in reverse. Society is attempting to minimize harm to itself, whether that's rejecting ideas that are socially harmful or demanding the decriminalization of activities that are not socially harmful.
Being made illegal or banned only makes things cooler. Marijuana is cool now despite being illegal.
Attitudes toward tobacco changed because of the power of advertising. There's a certain justice in that, since advertising made it popular in the first place.