What would it take for $ETH to switch to onchain governance?

Right now Ethereum governance is offchain:
Core devs propose EIPs, the community debates, and social consensus decides what gets implemented.
Staking gives you validator power and yield but zero say in protocol direction.
So currently even DeFi tokens like $UNI and $AAVE have more utility in governance than $ETH.
Vitalik opposes token voting for protocol governance as anyone with enough capital could buy 51% and capture governance.
But that's unlikely because the costs would be too great.
More importantly, Vitalik now pushes to 'ossify' Ethereum with less changes in the future.
In this case the remaining decisions are economic parameters like issuance rate, blob pricing, staking minimums, withdrawal timeline, slashing penalties etc.
And token model makes sense when 1) Ethereum Foundation's funding decreases and 2) high level ossification is achieved thus token model would actually strengthen Ethereum's neutrality instead of putting it at risk.
This would massively boost demand for ETH, as institutions and countries would stake and want a say in the monetary policy of a real global settlement layer.
I get that it won't happen next year, or this decade.
But time might come when Vitalik will want to retire, and trusting a group of people might put Ethereum at a greater risk than trusting self-interested $ETH stakers.