You are right, investors better get ready for it and keep Holding their coin because anyone that sells off now at this critical time is doing so to his own detriment, I will also advise those who are waiting for bitcoin to fall back to $4000 dollars or below before investing to rethink their actions as it will be impossible for BTC to fall to that price again until we see the ATH.

I am not sure what will happen after the ATH, it depends on motive behind every investment, I believe we have big percentage of people keep their funds in BTC other than that of investment, so $4000 may never even be possible again as people adopt the crypto now for various purposes.