train groups of young people to socialise romantically and sexually with the opposite sex to replace substance-assisted romantic and sexual initiatory behaviour.

Alcohol works as a 'social lubricant' to make people less inhibited, in moderation it's very effective at what it does. It also works quickly and is cheap. There is also a culture and set of traditions around alcohol, as well as a powerful industry lobby.

I pity the fool who tries to compete with something that is so good at what it does, especially with a 'training program'.

The only way I can see alcohol being dislodged is with another drug which is specifically engineered to be better than alcohol at what it does (reduce anxiety, provide an excuse for people to get away with things, etc) but also has none of the problems that alcohol has.