They might not have topped themselves but we've also had the likes of Merson, Adams, Mutu, Bosnich, Gascoigne, Maradona and plenty of others that have got caught up with drink, drugs, and gambling problems. With the drugs ones it could be the case that the testing in football has caught them before it's gone too far and the shock of facing the end of their career has been the intervention they've needed to stop it going too far (although would you bet against Maradona ending up dead that way?). Obviously there's Best as well but that's going into a different era in terms of social conditioning towards drink.
And I've just thought, the team nature of football means there's more likely to be someone around who'll see the signs of their personality changing and can raise concerns with an authority figure like the manager. With entertainers, it's a lot more solitary, and although they have managers it's generally the artist that's in control.
You look at someone like Cairney, if he starts going off the rails or getting big headed (some would say he has) there's NP in place to drop hiim from the side, tell him it's unacceptable and show him that his career is determined by others being happy with him rather than being solely him. Then look at Andy Murray, if he got into that mood what cna his coaches etc do? They can't stop him entering tournaments, and he doesn't need a club to employ him. It's similar with entertainers, alright they need record labels or directors, but at the end of the day they're not tied to working with one, if they get sacked they can go independent so it doesn't matter what they think.