An ounce of prevention is worth a pound of cure.
I would like to see a permanent testchain that is upgraded before the primary chain. In order to flush out and avoid issues like we are seeing with the Granada upgrade ( and the kinds we have come across in the past ).
I don’t think it necessarily needs to be subsidized. Perhaps in the beginning. I think a testchain where the value of the coin is forced to zero ( thereby making all transactions non-taxable ) could be used as an onboarding opportunity for people to learn crypto without risk.
Which also makes it a fantastic marketing opportunity.
You could force the value to zero by making the coin centralized and explicitly stating that you will delete the balance of any exchange addresses.
Since it’s not necessarily meant to be decentralized a node owner could allow access to testing teams. Those teams could update or roll back various parts of the networks version in order to test varying conditions or simulate the current conditions ( or whatever desired ) of the mainchain.