Projects and investors might have to find an alternative to the ethereum blockchain. But this will not happen in a short span of time, it will take years. There are a lot of blockchains out there which offers better speed and lower fees.

Ethereum 2.0 will make the network scalable, and therefore decreasing the transaction fees in the long run. So this should not fail. There will be delays but I'm confident that the protocol will give much more room for growth.