It hasn't reach 20k in 2020 because 2020 isn't over.

We still have enough time for volatility to do its thing so let's cross some fingers and just watch the outcome.
Besides, I think we shouldn't be too obsessed about the whole price thing. Bitcoin is not about it's price... But it's use-case.
I reckon with your humorous response. The year 2020 is indeed still ongoing and it's not over until it is over.
Personally, I expect it to hit that 20k mark by the 31st Dec, even though resistance has been so strong at that point.
But whether it gets there or not, I reserve a lot respect for the king of crypto. It has done very well in this financial year.