[krfsm]

As others have said, those other coins will get increased competition splitting the mining returns. Unfortunately (for the miners), Ethereum is vastly bigger than all the other coins.

I checked whattomine a few days ago and compared the hash rates of each coin. To make it simpler to compare, I converted it into RTX3080 equivalents. With this measure the hash rate for Ethereum was equivalent to mining with a bit shy of 10 million RTX3080s.

Ethereum Classic, which is the second biggest coin listed on whattomine, had a hash rate equivalent to about 263000 RTX3080s. I.e. Ethereum has 37 times more miners than Classic, and if they all moved to Classic the revenue would be slashed to 1/38 of what it is now while everybody would incur the same costs as now.

Ravencoin is the second biggest mineable coin (Monero isn't profitable to mine even now, so it does not matter) and Ethereum is 83 times bigger than Ravencoin.

It turns out Ethereum is more than 16 times bigger than every other coin listed on whattomine combined.