Anecdotally, I've been playing WoW almost non stop since it launched and have been raiding once to three times a week. During this time I also got married, had a kid, founded Shopify, overtook the CEO role, grew it to be a multi million dollar business. In this community that seems far from being a failure.
I'm engaging in anecdotal junk science here but my theory is that the people who really loose themselves in games like WoW are people with very poor time management skills. I'm convinced those people have always been around before. However, previously almost all activities came with some inherent caps on the time you can productively spend on those. All sports wear you out and force you to stop after some time. TV repeats pretty quickly and there is no original content during the night. Reading works but that's a socially fully acceptable timesink.
WoW is just extremely good game that fulfills a lot Maslow's needs, especially the top ones. There is a great asymmetry in the lure of this game and the established defenses of some people.
I think one of the key parts of parenting for our generation will be to equipt our children with the time management skills and the willpower to handle and enjoy games like WoW properly.