I think it depends on the person. I think we all know of people (heck, check Craigslist!) that get gliders, or any type of animal, and as time passes and other things come along, the "newness" wears off.
Personally, I fail to see how that could happen with gliders....they are each individuals, have their own personalities and quirks. They are animated,...they can be sweet as pie one night & full of piss & vinegar the next.
IMO if people get bored with their gliders it's because they don't spend enough time with them.