Mustaches have become a really popular thing in the last few years. MMM caught that wave at a good time.
I expect it to die out as a fad in a year or two.
When that fad is over, then they will come back as zombie mustaches.
Zombies are a great example of a fad that was hot a few years ago, is less so now, and I expect to continue dwindling. Mustache products are everywhere right now (one of my coworkers had fake mustache stickers on her desk the other day, and you see them on coffee mugs, etc. etc.), but give it a few years and it'll be cheesy again.