I can see the War on Drugs more broadly becoming more salient as states move to end it entirely, with Oregon currently at the forefront here, but I think 'marijuana' as an issue in and of itself is close to its expiration date.
Increasing legal and social acceptance of marijuana is going to precipitate an eventual public health/"save the children" response by the 2040s/2050s. It is on a similar trajectory as smoking.
I wonder to what extent these are even possible in the current media environment, and while the 2040s/'50s are hard to predict it seems like media splintering is probably likely to continue rather than reverse. I wonder if the anti-smoking campaign wasn't the last successful large-scale public health campaign aimed at changing individual habits that we'll see for a long time.