Another thing to consider is that Melkor was never known to show understanding or mercy to his servants who failed him. I would have to think that any balrog who failed to come to his aid would have been killed (or worse as you postulate) as soon as Morgoth was freed.
Hah, now I'm imagining an alternate, sillier Arda where the balrogs had the same conversation as the villain's abused lackeys did at the end of Disney's Hercules. (A really underappreciated movie, IMO. Just don't watch it expecting it to be about the Greek myth.)
He's not going to be happy when he gets out of there.
You mean if he gets out of there!
If. If is good...
The dip only lasted a few months. By August of 2020, VTI was back to where it had been before the dip in February.