[In 1992, t]he country was tired of the partisan bickering in Washington and didn’t see a dime’s worth of difference between the two major parties. ~Edward Rollins

That is probably mostly true.  There wasn’t a “dime’s worth” of difference then, and there’s probably not even a nickel’s worth today.  What is so bizarre about the would-be Bloomberg or Unity ’08 campaigns is that both are premised on the strange view that the two parties are radically at odds and farther apart from each other than ever as they allegedly race to opposite extremes.  Independent candidacies flourish when they cast the major parties as an indistinguishable, self-interested blob that gives people no real choices on major policies.  They also flourish when they offer a clear alternative, not congealed, reheated slop that combines the worst of both existing options.  Were he to run (and he isn’t going to), Bloomberg would be likely to serve up the latter, and not even $500 million or however much cash he could throw at the electorate would make them want to swallow it.  He might get a decent 10 or even 15% as a protest vote, but that would be all.  His positive platform would have to be able to address what the major parties have missed, and as of right now there is no reason to think that he even understands what those things are.  As Ambinder pointed out, he is prone to saying absurd things like this:

“I’m particularly upset that the big issues of the time keep getting pushed to the back and we focus on small things that probably only inside the Beltway are important,” he said. “When you talk to people around this country, they care about who’s going to pay their Social Security, they care about who’s going to pay their medical care, they care about immigration, about our reputation overseas.” Nobody is willing to talk about those things,” he said about the issues.

This seems to make Bloomberg into the Tim Rutten of presidential candidates: other people may be talking about a subject, but it doesn’t fit his preconceived notions of the way the world is and therefore it is obvious that nobody is saying anything.