I also disagree with this line and the general thinking of the OP. We
have seen on occasions the markets move for no known reason. I have
seen many supposedly stimuli events in 2017 which resulted in the
markets moving in the opposite direction to the desired one.

If there is a stimulus it may not affect the market immediately. For
traders there is a saying which can be applied to any sort of event
or stimulus, "buy the hype, sell the news"

I cannot see any one "realistic" thing which would affect the crypto
space which would stimulate the markets into a massive rise, it will
be a number of events over a space of time which will result in the
desired affect.

Example of unrealistic events:

The return of Satoshi
Global acceptance of Bitcoin as legal tender
The U.S and China to ditch the Dollar and Yuan in favour of Bitcoin
Bitcoin price falls to $10