I agree, but I am quite optimistic to defend this attack (e.g. buying a short and then shadow mining) for the two following reasons (and because we have these defences attackers are discouraged to even try):

• the shadow miners that have a stake to attack the network spend computing power to remine x old blocks and publish when they are y blocks ahead. In order to do this they have to use much more computational power than just mining x+y blocks because the honest miners dont sleep. But once they publish, all honest miners (contested mining rewards), the stakeholders and the long positions have an interest to remine the original chain. And to do this they do not need to remine x old blocks, they only need to get y blocks. After the shadow miners have already committed to remining x+y blocks, it becomes a race where they have only y blocks advantage over the honest miners. In addition their stake is always smaller than the stake of the honest miners since every short is also a long plus the marketcap and mining rewards (difference in stake of x blocks). So it seems that the shadow miners are at a double disadvantage and are set up to fail and it is only a matter of time until the honest chain is restored.
• This brings me to the second point. Since it is clear that the shadow chain will almost certainly end up orphaned, some consensus nodes will immediately reject it by checkpointing. This may be done via a fork, where no sane investor would give any real value to the shadow chain, or as a 'temporary' service, to let people see what happens on the 'real' chain and continue to do transactions there in the meanwhile. In both cases, the value would be with the original chain. Even the code is law people may use this, since they know that the shadow chain will be orphaned and there is not need to wait for it if it will happen anyway.

Then if I am correct, the attack will not end up doing much. But what we need is seeing this happing to discuss the strategies and solutions. This is why I am still hoping ABC will be attacked.

Also note that a fork introducing a checkpoint to dismiss a shadow chain is still decentralised. Nobody is forced to use this side and people are free to use the coin supported by the shadow miners. But why would they, what is the value proposal of the shadow chain. And if the shadow miners do not also put in their own checkpoint to prevent a future reorg, it will be overtaken anyways.

It comes down to saying "Okay you mined a lot of blocks that are compatible with our consensus rule, but you miners are there to provide a service to us and clearly you did not do that. So thanks for mining all these block, but we dont need them. And then moving on with life while leaving the attackers ruined. "