It doesn't matter, IMO of course, if the airline charges £8 for a can of beer or it's free the whole way to Miami, people who want to will still get loaded up at the airport before they fly as it's seen as a vital part of the holiday in many cultures, especially the UK and ESPECIALLY with young groups which so many of these stories involve.
Aside from the usual Greek and Spanish Island, Turkish and Black sea resort charter flights, places such as LAS are sometimes in the news for disruptive passenger behaviour and they are almost always on full service carriers where alcohol is free. The airlines cannot control what happens on the ground, so the problem could be passed on.
Airport bars and restaurants could have a drink limit per person as we all know the effects of booze can take a while to kick in and at 33,000 feet the process is exaggerated anyway, so nipping it in the bud seems sensible. I'm sure some would protest, but it'd certainly cut down on a lot of the behaviour. I imagine the vast majority of airport users in a bar or lounge are there to relax anyway and aren't chugging down the pints and cocktails like the "lads on tour" lot do, so having an alcoholic drink limit most likely won't actually affect anyone other than the people trying to get drunk before a flight.
The problem of drinking duty free onboard is harder to tackle. Locked overhead bins would only stop people getting important things during the flight and having crew unlock them on demand would ensure they'd never get anything else done. Tamper proof bags which cannot be opened without a knife (which would hopefully not be onboard) or some kind of system where any duty free bought is sent to the aircraft hold and the passenger collects it on arrival...but that is not going to be practical or cheap to roll out either and people would find a way around it if they were so determined to get drunk.
A lifetime ban is overkill, but stopping them for a few years, maybe 3 would be good, with longer bans for more severe troublemakers or a lifetime ban for repeat offenders. It won't stop the first time offenders though and no doubt the "human rights" brigade would be all over it.