After the Ethereum 2.0 update I won’t be able to sell my coins?

Ok first of all I hope that it is alright to post this here and that it doesn't belong to r/ethtrader.

The statement in the title is what someone told me and why he thinks that the ETH price will drop after the update. Could somebody tell me if that's true and if so why that is the case.

Sorry for that "nooby" question. I really love the idea of Ethereum and I am invested in ETH since I love the idea of it but I'm still kinda unfamiliar with the exact mechanics and trying to learn slowly about it. So help would be appreciated :).