I know this from first hand. Unfortunately immense electric price increase in democratic and wealthy countries are favoring altcoins for mining. And when they are mined than they there is quite big marketing around done by miners also. With electricity price over 9 USD cents there is no reason to mine bitcoin .Nevertheless we know from past that bitcoin tends to be more sustainable but nobody knows future. On the other hand there is saying: all altcoins were made just to take your bitcoin.