It's just like you say, before splitting a block from 12.5 btc in half, there's always madness and people are buying for a lower price. I don't think bitcoin drops after splitting, somehow sharply. I think we'll wait a little longer for ATH.
That is the thing about the all time high, just because we believe that there will be a pump and there will be an increase, which means we are all bull about the price, doesn't mean that price will go over 2x in price. Right now it is around $9.9k and that is fine, x2 of that is about 20k, that is all time high, sure it is quite close.
So, we are talking about bull versus all time high, I do not believe bitcoin will drop, I think it will go up, I think 12-14k levels are realistic after the halving, but all time high is just way too much right now. Plus it is not even about x2, we dropped to 4-5k just recently and already did x2 if you look at the right places, but moving from 4.5k to 9k is different x2 compared to going from 9k to 18k, those are very different.