I am willing to bet in 5 years time, the largest crypto currency will still be BTC and it will still be POW.
Why should cryptocurrency be singled out? Just because some people dislike it? We haven't done much about climate change and the big pollutants in decades, but as soon as cryptocurrencies come up, it's suddenly treated as an existential threat to human kind - I don't buy it.
If we are talking about climate change, time is quickly running out. So talking about wishful thinking while reality is actually other way around does not seems to be helpful.