There's not much to profit from the price difference bitcoin made lately.
Maybe not for you, but for enough traders it is profitable. Every minor price movement can be a worthwhile scalp with leverage. How do you think a boring asset such as gold is being traded? Leverage is key.
If holders are not in a hurry and don't need money that much, better leave their bitcoin secure for now in their wallet and wait patiently for a real bull run in the market.
Why do you assume that people speculate with their entire coin stash? In most cases people's speculative coin stash accounts for less than 10% of their total long term hodl stash.
As for the 'real' bull run you're talking about, it can't get much more real than going from $4000 to $8500 in a short period of time. Your 'real' bull run definition is probably based on a 500-1000% increase.
In bitcoin there are no 'minor' movements, minor movements are 2-3% which is considered huge in stocks. Even with a 1000$ investment, a 2-3% gain is still 20-30$ in one trade. That's huge, this market is definitely the best for small investors if you know what you are doing.
Yes, sentiment has clearly switched, trends too, only the monthly trend left, all the others are already in a confirmed uptrend.