I've known Tom for a long time; he's a very hard worker and turned the restaurant into a nice franchise. My impression has been that, for a long time now, the restaurant has survived by living on it's prior reputation. It's a tradition to eat there, for the neighborhood. Add to the tradition Tom's high-profile in the gay community and the proximity of the restaurant to the heart of the north side gay community - and you have a sure-fire forumla for long-term success.
I, too, have never been impressed by the food served at the Belmont Ave. location. I've booked some parties in the 2nd Fl. of the just closed place, and it was a convenient location and meals were reasonably priced and the waitstaff was excellent. A draw for the restaurant is the free parking for customers, behind the restaurant. (one of the reasons for the success of The Bagel, IMO, is it's free parking - also).
When Tom was elected Alderman he gave-up his liquor license, and I suspect that hurt some of his restaurant business - and a lot of his banquet business. Though, a banquet BYOB (without a corkage fee) policy is very attractive to many party planners. A new chef was brought into the business when Tom went to City Hall (though he's still working in the restaurant when he can) and the change in menu and rise in prices seemed to alienate many long-time customers.
I know the new space the restaurant will move into, another of Tom's properties on Belmont Ave. (on the E. side of the driveway between his buildings, that leads to the rear parking area).
I've been to the Ann Sather's on Broadway (between Belmont & Addison, right?) and I'm expecting this new Belmont Ave. place to be similar - a storefront restaurant. Overhead will certainly be less in the new place.