I think you should check out the first post in this series: Hardfork: the tale of the full node referendum. Any blockchain can just fork when they need to. The thing that matters is consensus.
Regarding the upcoming hardforks, they are no big deal. ETH has done them a number of times (most recent just a few months ago, next in about a month) - hard forks are no big deal. All they are is protocol upgrades. If the switch to POS is contentious then there could be 3 Ethereums. Not sure why it will be contentious, the switch to POS has been on the docket since the beginning.
There is certainly a lot of complexity and uncertainty. Hopefully I can stand as a voice of reason - remain skeptical.