Actually I don't believe in rising price, I guess it's take some time to check is it really working without any bugs. The price will rise in a few weeks, as it did with Bitcoin after it halved.
This scenario is possible for ETH 2.0. Remember that neither after Byzantium, nor after Constantinople, there was growth based only on the network update itself. And this is only if the 2.0 update does not compromise itself due to the presence of critical vulnerabilities in it.