no, price probably won't wall to 400$ anytime soon as price now is too high to fall there because of pump and dump, and price will even rise because of halving
The price will not easlily go to 400. Because many miners can't make profit with with just 400 dollar per bitcoin times 12.5.
I think the mining farms will push the price up again when the price comes near 500 dollar.
That is right. The mining cost is more than $400 for many people. They will not sell the bitcoin below cost.