all asics out > high diff > bitcoin over 300$+?
no. difficulty follows price, not the other way around.
... it is not just that simple, more nuanced than that ... as vladimir is saying, I think?
I think so. One of the attack vectors against Bitcoin depends on network hash rate (i.e., difficulty), so one could argue that higher difficulty will make potential attacks against the network more costly. Assuming that the price of Bitcoin factors in this very potential cost, higher difficulty will give room for higher price IMHO.