I really wouldn't be surprised at all if the entire cryptocurrency market cap just started to collapse after this year, perhaps to 50 billion. This would obviously mean that a lot of people will be losing money and whatnot but also would be a great buying opportunity for anyone that missed out on this ride.
However, i expect bitcoin dominance index to rise to at least 75% again despite this declining total market cap. Alts are in a much bigger bubble than bitcoin at the moment, in my opinion.
Over the long run bitcoin is extremely bullish at least to me, but short run price is still extremely volatile.
No, I never thought it would collapse, look at what happened, it has grown tremendously, especially recently, many people say that we are all in bubbles, and it's fragile, but I think it's still cherished, and it will not break.