What could be done from now to prevent this?
If you're a miner ask your pool if they're going to support Core 30. If there's no response, switch to a pool that clearly won't support this craziness.
If you run a node, you can symbolically run bitcoin Knots as an alternative. Mining is what makes a difference so keep in mind that node running is just symbolic.
Keep it this way...Hello World Of People Irrespective Of Your Privacies, "between Centralization and Decentlization which do you appreciate if you prioritize self custody your right and interest?
With all being said of Jack Dorsey are part of the issues Satoshi Nakamoto has sighted and and avoided and made Bitcoin be just in that concepts as stated in the white paper and so on being realistic.
Bitcoin most interest for users is the Decentlization, maybe we can for now say it is its potential to store values because we consider most fear and concern to fight inflation first. However, the assurance of your funds safety is when it is of no authorities control but yourself.
So throw the question as stated to the entire Bitcoin community or enthusiasts because if only developers may have choosed to reinstate the decentralized system of Bitcoin to be governable with Jack Dorsey's ideal if not (speculations), I would say.... Blockchain and its Decentralization won't be so admirable for users as it is from it origin of Satoshi's development concepts that made self custodial a privilege and right for everyone in the cryptography of Bitcoin cores which has brought the stance of massive adoptions of the technology as a means to keep custody of their Privacies.
(If) Paraventurely Jack Dorsey and his teams succeeds this agenda, then is a goodbye to decentlization and an end to Bitcoin because adoption will be dumped by users therefore, Jack Dorsey proposal will be abolished even by the developers because they too values that concept (Satoshi) stated that respects their rights respects privacies. So don't expect them agree to Jack.