Exactly my thoughts - it's going to be a slow decline. Probably the first thing that will happen is that mods will drift away and the quality of subs will decline. Any replacement mods may be good but are also just as likely to drift away after a month or two.
The site will slowly attract more and more spammers and scammers when they wake up to this fact... Whether it actually disappears I don't know but it will become irrelevant by becoming more bland and corporate in an attempt to chase money. It'll end up being more like Tumblr or something I reckon, something that exists but only some people actually use.