It doesn't work that way. The cost doesn't double because many miners drop out. Regardless, the price does not depend on the cost to mine. It is the other way around.
Quite all right, I don't agree totally with the OP - especially on his forecast about the $90,000 Bitcoin price. No one honestly knows where the price of Bitcoin is headed. We have seen experts make predictions in the past and how reality made a mess of their predictions. However, I do agree that Bitcoin halving definitely will have a ripple effect and one of such is "scarcity" Scarcity creates room for price appreciation. And this is certainly what we will experience in weeks to come, especially after May.