If the gas price is not reduce after starting ETH 2.0. People will seek for another blockchain. This cause the user of ether will decrease. One day ether will lose their user.
I remember when people have said the same thing like you in the past and they are not yet moving from ethereum. Maybe the demand will decrease a little big compared with this time but it's clear that the ethereum 2.0 will bring something big for all of components in ethereum blockchain started from the scalability, consensus, passive reward, less inflation and many more.
It's quite impossible for ethereum to lose its demand just because the scalability problem is not yet fixed.