The shift from mining to staking on major networks removed the energy criticism almost entirely – consumption fell by orders of magnitude and the change held.
What it did not resolve is who ends up controlling the network.
How it works
Instead of spending electricity to compete for the right to add blocks, participants lock up currency as collateral. Misbehaviour costs them that collateral. Security comes from having something at risk rather than from having spent something.
The concentration problem
Running a validator requires a substantial minimum stake and continuous reliable operation. Most holders meet neither condition, so they delegate to services that run validators on their behalf.
Those services concentrate. A meaningful share of total staked value across major networks sits with a small number of providers, which reintroduces exactly the concentration that mining pools produced under the previous system.
The mechanism changed and the outcome rhymed.
The compounding issue
Staking pays a return, and that return accrues proportionally to existing holdings. Large holders get larger relative to small ones, permanently, by design.
Under mining, staying large required continuous reinvestment in hardware and energy. Under staking it requires nothing.
What has worked well
Security has held. The predicted attacks have not materialised at scale. Finality is faster and more definite than under mining. Energy use is negligible.
On the technical objectives, it succeeded.
The open question
Whether concentration among staking providers eventually matters. It has not caused a visible failure. It is also the kind of risk that does not cause a visible failure until it does.