In fact it could probably be argued the only reasons these programmes survived at all was because they all tried to do things differently with failing results and so reverted to emulating the (later) model that TV-am had hit on. I don't know what the actual ratings were like for TV-am in 1991/1992 but they were the most successful and popular breakfast TV channel at the time.
Well, it's no surprise, really, look at the competition at the time. Peter McHugh talks about it in Morning Glory, in the early nineties you had Breakfast News, which was a very boring programme indeed, The Channel Four Daily which was absolutely an acquired taste (McHugh: "I watched it and I couldn't believe it had got on the telly") and BBC2 had either the Open University or a blank screen. Sky was pretty much an irrelevance. So where else was the mass audience going to go? It was TV-am or nowhere.
The problem GMTV had was that The Big Breakfast then began so all the families with children than GMTV assumed were going to be there and were counting on weren't. Of course, The Big Breakfast went off the boil incredibly quickly and by the mid-nineties GMTV was enjoying almost as much of a monopoly as TV-am had. It was never going to go bankrupt, though, the fact it had tiny overheads compared to TV-am counted against that, Greg Dyke says that it would still make money for LWT and its other shareholders regardless.
There's another thing McHugh says in Morning Glory about TV-am becoming GMTV that you could well apply to GMTV becoming Daybreak. He said the assumption was that the viewers would come flocking to GMTV because TV-am was an absolute joke in the industry, nobody had a good word to say about it, and now you'd have a proper professional service - but the viewers didn't know that. They liked TV-am. And similarly when GMTV ended it was a bit of a toxic brand, they'd had all that trouble with the phone-ins which really damaged it and the audience was ageing and declining - but again, the audience weren't really bothered about that.
The other thing is that Daybreak is an absolutely cursed name and I don't know why people keep on using it. The original hard news TV-am programme was a disaster, the consortium of that name failed to win the franchise in 1991 and this was a flop. It's completely plagued!