What's the point of living a life free of vices?

(Firstly I’ll presume that you meant to end by writing, “…far, far more rewarding than that.”)

Every human being experiences only one set of human sensations, namely their own. You can never experience the exact experiences of someone else, only hear or read their descriptions of experiences and try to judge them by your own experiences. Hence when you judge these non-drinkers to be joyless clods and you claim to have had more fun, what you’re really saying is that their explanations sound less fun to you than a drinking experience. There can’t be an objective comparison of fun levels. It may well be that these people have the capability to extract levels of fun from their non-drinking experiences that you’re not aware of.

Well, then, they don’t have any difficulty in seeing that life would still have a point even without those particular enjoyments, and thus are not the subject of the OP.