What is the "honest" distribution?
An essentially random one :-)
Anyway, more than 90% of bitcoins will be created by 2024. I have no idea what you are talking about re ecological disaster.
Mining equipment gets more and more energy efficient.
That doesn't matter. What matters is the inflation rate as compared to the market cap: it gives you the amount of resources that will be spend grossly on mining equipment and electricity consumption.
If bitcoin takes over all of fiat, say, in 2024, after 2 more block halvings, inflation rate will still be 2.5% or so.
That means that 2.5% of the world economy will be spend on mining equipment and electricity in principle.
All of world economy (all of M2 fiat) is about 55 trillion $. 2.5% of that is about 1 trillion $.
If half of that is spend on electricity, mining will spend 500 billion $ on electricity. At a price of 0.1$ / KWhr, that's 5 trillion KWhr or a power consumption of about 570 GW. Now, that's about a fourth of all of the world's electricity production today.
So one fourth of all electricity production would go into mining if by 2024 all of fiat was taken over by bitcoin.
No matter what "efficient hardware" is running.
Of course these are ballpark estimates, and factors of 2 or 3 easily off.
If this happens 12 years later, in 2036, we would be 3 block halvings later, so everything would be down by a factor of 8. That starts to be more reasonable.