As I said near impossible to occur.
For one, this is a 51% attack and if this occurs bitcoin is dead.
And this scenario assumes miners=bitcoin which is true. Miners along with others control Bitcoin.
Economic nodes you might say formally-help decide bitcoin along with miners.

And as you said before the damages would be great. They wouldn't gain anything out of it via bitcoin. They can however earn via fiat based bitcoin shorting. Assuming they can use the fiat without KYC....

Can it happen? Yes
Will it happen? Most likely no.

I really wouldn't worry about it actively.