No, no, no it shouldn't be that easy
- Step 1: they need to change the algo to X21S, like one of the proposals
- Find out if anyone can just rent GPU hash rate these days to do the same again
- Step 2: cut the reward
- Find out they have just less miners and the chain will be attacked with $1000 worth of gear
- Step 3: move to POS
- Realize Coinbase, MSTR and etc could also just reach 51%
- Step 4: invalidate all previous balances since the split
- Look in the room and see there are just the 3 or 4 of them left

Earlier today Cguida (dathon ohm) threatened someone with a ban for suggesting that blacklisting coins wasn't a good move for an open and decentralized blockchain--
He should really change his name to Captagon!
In any case, it does look like people are figuring out how to prevent replay ... and I haven't yet heard of any big replay loss disasters, but in the past the losses were a bit delayed when the second wave were a little less cautious.
As time passes, there will be less and less of an incentive to sell those coins, with BCH the coin was going up far closer to BTC value..here..
I thought about selling when I saw 1200, I actually decided when it was $800, I sold only half a coin from one of my wallets at $620 and the spread and the fees eat up about $50 of those and now the price is $300 Not much in terms of $, but I still feel great knowing some blakie paid that much for their shitcoins.