Sounds like they didnt ban it properly. There aren't really nicotine junkies like heroin. So I suspect ban nicotine and slowly everyone stops using nicotine sources.
There were two countries in the 20th century which tried to ban alcohol. Both had a.. very lasting consequences.
You can't "just ban" it or "ban it properly". You would get a very nasty black market and things with such ban.
There aren't really alcohol or cannabis junkies like heroin either. That didn't make prohibition or the war on drugs successful.
Everyone I know who vapes nicotine is a junkie about it.
In fact, nicotine habits can be harder to kick than heroin. I know plenty of people who have tried to kick nicotine many times and cannot stay off of it.
Anyway, it's moot, because outright banning tobacco is insane.