Greater fool theory works great until you run out of fools! With the amount of attention that bitcoin got, I feel we are close to tapping into the last of the fools.

Institutional investors via Bitcoin futures ETFs[0].

It will likely result in a lot of money flowing into the market via funds and investment houses where investors seek to diversify their investments.

That will probably bring the cryptocurrency market back up to $20K and above. It probably won't happen until 2019 or 2020, though. The SEC is still on the fence about it, but I see it as an eventual inevitability.

[0]: https://www.coindesk.com/sec-bitcoin-futures-etf/

Good grief, I hope that does not happen. I think any professional financial services people who blatantly speculate with clients' funds should be on the hook for criminal penalties. It's one thing for Joe Blow to play the speculation game with his own money, it's entirely different for a professional to do it with everyone else's.

Don't worry, the SEC has now declined to approve two separate attempts at a Bitcoin-based ETF, both times citing the extensive manipulation of Bitcoin markets as one of the reasons. I don't see them changing their attitude given that rampant market manipulation is the main thing keeping Bitcoin alive at all right now.

Trouble is Joe Blow often wants it. You say you want to invest in this thingy that seems to go up 100% a year or nice sensible bonds and quite a few will want the thingy.

Bitcoin does not maintain the higher value due to "more gamblers", it only has value due to "more holders". Gamblers can come and go and affect only the volatility. But people who stay and hold for years and sell only a small fraction to pay the bills.

Sidenote: that last statement is often confused with "rent seeking", which is not the case at all with Bitcoin. Because it's virtually impossible to make more Bitcoin with your Bitcoin. There's no any sort of business that can give you a better return at the lower risk. So you don't live on the "rent", instead you live off "wasting your savings", although if you were patient enough for them to appreciate a lot and you spend <10% a year, you have a decent chance to keep the total value growing and not shrinking as time goes by. But you need to be frugal.