In the meantime after a year of the US government printing 20% of all dollars ever made, perhaps an alternative form of currency is a slightly more complex issue than just it destroying the environment. Maybe some people realise the monetary crisis that's inevitably coming.
It is about a proof-of-stake scheme like ETH2 where the blockchain is still immutable, but due to a purely abstracted notion of "mining" which rather than electricity at all relies upon mechanisms where attempts to mutate the blockchain turn into pointless losses of money.
It is fully trustless, and I would argue even more trustless because it is accessible to all users, unlike mining.
The issue will be getting people to use something other than Bitcoin, not solving the technical challenge. Bitcoin mining will always be Proof of Work, and thus energy-intensive.
"proof of work", is by definition waste.
They will have to do something than increasing difficulty and and an ever increasing transaction log, as both are unsustainable.