On WPVI's message boards, they noted that attempts were made to find some kind of alternative with the loss of 87.7, but nothing panned out. Just because we didn't see it come to pass doesn't mean they didn't consider it and try to do something about it. Really, though, what are viable options? HD radio? It's barely on the radar and probably not worth the effort to many people. I would consider getting one installed in my car for that purpose, but I don't pretend to assume that means many others would do the same.
On the signal issue, interestingly, when I re-scanned last night, I got WPVI DT more clearly than I had been before. Whether it was a fluke or not, I don't know, but prior to June 12, I had horrible signal issues, and by last night it was showing a moderate strength signal with few freezes.