It's just a coincident. It can happen anytime current price of bitcoin is $12750. We may see bull run either by end of this year or next year but again it's just a speculation.
Remember the bullrun already happened at the first quarter of this year and then bitcoin and crypto were getting dumped again to the bottom.
Then a few months after that the bullrun is coming again and that makes bitcoin can grow even more.
The pump can occur anytime and it can't be estimated to come every 4 years from now.
If people have their faith on bitcoin and they will not care about that.