I think people are trying to read the tea leaves waaaaaaaaaaaaaaaaaay too much on this Carmichael's closing. You've all touched on the issues, but what it comes down to is this:
1) His prices jacked way up, to the point that it wasn't worth ordering there. The food was pretty good, I'll give it that, but a bill for a family of four could approach or exceed 50 bucks. That's a bit much for a night of pub food. My gut says that as profits decreased, Bill countered this by raising prices -- and kept doing that. Economics 101 tells you that once you start on this trend, your business will be going under eventually.
2) Much more competition than there was 10, 15, 20 years ago. Pyzano's, Uncle Jack's, Niner's, Patrick's, El Jinete, etc., not to mention all the Chinese restaurants that have popped up.
3) Ownership wasn't always the most pleasant to deal with, for either the customers or the staff. I have a relative who swore off ordering from that place because of the way he was treated.
4) The place felt like a dungeon inside.
I think all that adds up to a recipe for disaster -- especially the increase in competition. People just have more quality options now, and if those options meant you didn't have to pay Carmichael's prices or deal with Bill any longer -- well, you see what happened.
I quit eating there 13 years ago due to a manager's treatment of me as I was a regular for lunch there and was told I would need to order before 10 am for lunch. Sorry never went back.