High gas fees, reduced popularity of DEFI, rapid decline of TVL on the chain, distrust of ETH2.0, criticism from miners, and restrictions on participants by the POS mechanism. Will the challenges of new technologies and new public chains cause ETH to decline rapidly?
It should happen when you think logically but it is probably not going to because there is so much greed and that greed will keep ETH alive. The number of people who want something for nothing is basically infinite and that means it will create infinite demand for eth till those people lose everything they got.
On the other hand, those "new" blockchains have been trying to dethrone ETH for years and none of them succeeded. That means ETH is doing it right while others don't.