Bubbles are quite common in human history, whether they be tulips, south-sea, Mississippi, the 1929 stock-market, the 1978 gold mania, thoughout human history there have been bubbles.
A tell-tale of the bubble, is the parabolic rise, 20X in one year like BTC 2017 is a parabolic rise, one thing with all parabolic rises in human-history, they always come down.
The only mania that came back ( even for a short time ) was south-sea bubble, it was a dead-cat bounce, that even wiped out sir isaac newton, so it shows you have its not just idiot that venture back into a collapsed bubble,
But one clear pattern of bubble collapses, is the time to return, now with tulip, south-sea, Mississippi they never really came back, but the stock market post 1929 did come back, but it took 30 years, and the gold collapse post 1978-1982 bubble did come back, but it took 20 years.
On average it take 1-1/2 generations for people to forget they got wiped out ( 90% loss, or even 100% loss ), this is the nature of bubbles post collapse.
Today BITCOIN has collapsed down 90% year-2-date, and still dropping like a rock from a hot-air balloon.
The pump&dumpers say many things, ... it will come back, this bubble is different, BTC is not the stock-market or gold
Well BTC is just another time-series of data that can be statistically measured just like all others, whether it be rail-roads from the 1800's, or air-transportation from the 1960's bubbles are bubbles, and they always come back to earth. The question is do they return? and when do they return.
BTC is NOT valuable in and of itself, its only as good as its 'brand', thus BTC is much like the south-sea bubble, or Mississippi bubble those bubbles were largely inflated by fake-fiat, ,not unlike BTC today.
The other problem with BTC is that its easily duplicated, say now there are 2100 clones, and it appears another 100 added every month, as any idiot can copy&paste source, and add another clone; Anybody can fork BITCOIN and promote it, just like BITCOIN-GOLD which was sold for $500 before it was even forked in Russian futures.
BITCOIN was/is an INTERNATIONAL bubble, which is quite different than any bubble we have seen before, no bubble in the past has been on the INTERNATIONAL scale. The entire world speculated in BITCOIN in 2017, which is why it was able to rise to such a huge capitilization.
The problem now is there are 1,000's of lawsuits pending all over the world, because some +$500 BILLION was lost, some speculate over $800 Billion. Gone evaporated, which means millions of people lost their lost savings, they are angry, they are mad, and they will seek restitution.
A student of south-sea bubble, or Mississippi should know that post bubble many promoters were murdered and sent to jail. These kinds of bubbles never end well for those who promote them, e.g. pump&dump as seen here on bitcointalk.org
In summary, even if BITCOIN does come back, it will take anywhere between 20-30 years, over a generation for people to forget their loss. Certainly bitcoin will bump along, and have some value, but the speculative bubble we witnessed will not return, as never before in history, has a bubble came back in a short time period, and that's for the good-stuff.
A price of something is only as valuable as people will pay, the RISE of BITCOIN was largely the FED-FIAT post 2008, some $4 trillion USD were dumped on the world, and obviously $1T made its way to BTC, most likely the QE is over, which means that there is no source to re-inflate BITCOIN in the near future.
Most are aware that we're in a depression since 2008, and the future is dire for the USD, typically when the economy's of the world go to shit people invest in real assets, BITCOIN at best is a transactional currency, a holding-tank to transfer money A to B. Holding BITCOIN has 50/50 chance of total loss of capital, thus during a world depression people will not be parking their wealth in BITCOIN, but if millions use it day-2-day to move wealth around, the price will stabilize to some value ( IMHO around $1400 USD )