Wait what? Wasn't that depression caused by Mt. Gox's collapse? I mean, it was a giant exchange that was handling like 70% of all transactions worldwide. It affected a large portion of Bitcoin users, and I'm sure having your coins stolen isn't very motivating for you to continue any longer.
Either way, I don't see a collapse coming just because of the incredibly bullish run. It has never really worked that way. It may correct, yes, but collapses were usually preceded by some catastrophe that involves Bitcoin in a way, like how Mt. Gox collapsed. Not even China shutting down exchanges crippled it, when there were some people who legitimately believed Bitcoin would end there. Bitcoin is stronger than ever, but that may also mean that while it would be harder to bring down, it would also be harder to put back up.
By the time it died Gox had been long overtaken by multiple exchanges, but it did have a lot of coins still on it despite years of warning signs.
Some theorise that the long grind was down to stolen Gox coins, several hundred thousand, being laundered and sold but it was also for certain down to going too high with nothing backing it other than hopes and blag.
There are still plenty of potential ball aches - onerous regulations imposed in the US or EU, Korea doing a China.