The miners can choose to fork fork away from those changes. The core team is merely starting the change and the miners are supporting and carrying out those changes by continuing to mine the chain with those updates.
1. Producing blocks that abide to old rules will do nothing - client software will just reject them as incorrect. Fork choice rule (e.g. longest chain or most work done) applies when choosing between two valid blocks, not between valid block and invalid block.
2. Attempts to do a famous 51% attack is crazy expensive and have low impact. Why low impact? Because small events that are similar to rewriting history 51% attack does happen all the time. They are called block reorgs and all the software which uses blockchain as a data store have to handle it properly. Also, such attack will be perceived by users as attack on them, solidifying community around opposition to miners.
3. Targeting difficulty adjustment algorithm by mining on a fork and leaving it at the beginning of adjustment period. Lets imagine 80% of miners leaving. For Bitcoin it would create a situation when adjustment period would last 8 weeks instead of 2. Blocks would be produced every 40 minutes at average instead of 10. Ethereum is immune to this type of attack since difficulty adjustment is done every block, not every 2016 blocks.
May I ask you to elaborate? My point is - miners' power over the network is extremely limited. They are just a paid work force, working on a very small margin. They have almost no say where network will go in terms of evolution.
OTOH, I am not strongly against it, as decentralization doesn't mean every single aspect has to be free of centralized decision making (starting with the name, logo or the code). In the end, users decide if they want to use it or not.
Bitcoin could be entirely ruined by a couple dozen people around the world in different ways at any time. Eth and other coins even more so.
The idea of who “gets trusted” in these coins is just nuts. I’m not anti-coin... but man, I’m feel like I’m far enough from it to see a reality that many want to ignore.
That's different to e.g. PayPal where your funds can be locked and there's nothing you can do.
Decentralized control over name, logo, features or code of a crypto coin is extremely hard to impossible, if only because there aren't too many people alive that can discuss core crypto features with any meaningful knowledge (I know I can't). Some coins do have governance features, but none of those have profited very much from that.
Furthermore, crypto value is beholden on whales not to just dumping their vast hoards of coins into marketplaces all at once. That is to say, the largest stakeholders in a chain have the opportunity to crush the value of that chain, which means that they have power over other users' choice of chain .
Itslired by the great mystery of bitcoin, it’s like an appealing urban legend to say “we don’t know who owns all our coin by design! wink”. So this doubly makes the coin devs more powerful than “but it’s decentralized” people want to admit.
One - every Ethereum update is a soft fork of the protocol
Two - they are required to be soft forks by the very existence of the difficulty bomb.
Three - running a blockchain is already a social activity that requires everyone participating to opt in to the same protocol.
I don't think it would be easy, by any means, to convince the community to move a different direction than that desired by the core devs. But my main point is that the difficulty bomb is a mechanism to force soft forks frequently. It is not a mechanism to force any particular long term path.
Also because from the very first whitepaper it’s been known Ethereum would move to PoS.