If you're argument is that GM, as a sole entity, is competitive, you're somewhat right. However, I think your assertion that prejudices are misplaced is itself misplaced: the cars you've named are almost entirely new models, and three belong to Saturn, which is probably one of GM's lowest-profile brand. So while yes, GM offers some great vehicles, they're not nearly high profile enough to change prejudices. And more to the point, these good models do not overcome the perception of lackluster vehicles because they are overshadowed by higher-profile vehicles that deserve their poor reputation: the base-model Cobalt/G5, the G6, the Optra, Wave, etc...
Walking onto a Chevrolet lot is a painful experience, with only two bright spots on it: the Cobalt SS and the Tahoe (and the Corvette, for those that enjoy it 
).
If you walked onto a Honda lot, you would find three very competitive cars in the Fit, Civic, and Accord. By your own list, to find equally competitive cars in the same class from GM, you would need to visit two different lots, and even then you're only 2/3: they don't offer anything good in the sub-compact market.
That GM has some competitive models does not mean GM as a company is competitive. Of course, the reverse is also true: just because GM is overall still fairly lousy imo, that does not mean they offer nothing of value. 
I would agree that Honda is more consistent at making "pretty good" cars, whereas GM is all over the place with the quality of their designs. I would also agree that, in my opinion, the GM turn-around didn't start until this decade (first-generation CTS and the Cobalt replacing the Cavalier spring to mind), and they didn't start really nailing it beautifully until about the 2007 model year.
But here's my problem with what you say: you say that you can go to the same dealership to buy a Fit AND a Civic AND an Accord, whereas you need to go to two different dealerships to buy an Astra and a Malibu. But so what? I'm not going to buy two new cars the same day! Maybe the Honda way makes more sense from a corporate profit standpoint (though Porsche seems to disagree, seeing as it's about to take over the marque-heavy Volkswagen Auto Group). But for the consumer, it really doesn't make a lick of difference whether a company's five best cars all have one badge or five different badges on the hood. And I'm a consumer, not a shareholder.
Here's my other problem with Honda, as long as we're on the tangent of comparing Honda and GM and saying which we like better. Honda consistently makes "pretty good" cars...but they are currently consistently making "pretty good" cars that I personally have absolutely no interest in. I'd personally rather have an Accord over a Malibu, but I don't want either! I'd rather have a CR-V than a Vue or an Equinox, but I don't want any of those! The Fit's a very nice subcompact, but I don't want a subcompact. Et cetera. In the segments where I could actually envision
myself buying a car, it seems that nowadays I consistently prefer the GM option over the Honda option.
* Compact economy car? I'd much rather have an Astra five-door (especially with the available sport suspension) over a Civic. I like Teutonic driving dynamics, and I don't like Star Trek.
* Sport compact? I'd choose a Cobalt SS over a Civic Si in a heartbeat. I like
torque, particularly the turbocharged variety, and I don't like Star Trek any more when the USS Enterprise is lit with red light instead of blue. And while the Civic Si does indeed have remarkable handling, the Cobalt SS Turbo has a much better chassis than most people give it credit for.
* Upper-$30s (US) sport sedan? I'd personally much rather have a second-generation CTS than a TL, for a multitude of reasons.
* Just-shy-of-$30k (US) sport sedan? As flawed as the Saab 9-3 2.0T is, it really lights my fire. The second-generation TSX leaves me cold, and most reviewers (besides the Honda-loving C&D team) agree. For the record, the first-gen TSX was another matter entirely...I loved driving it and nearly bought one (but then I knocked my wife up and, in a spate of pre-fatherhood panic, bought the painfully dull and generally unpleasant Legacy which I likely will never stop whining about).
So I'm not a "GM guy." I'll freely admit that 2/3s their current line-up is total rubbish. But the remaining 1/3 include
several cars that I, personally, would actually want to own. Whereas I, personally, only like
one car that Toyota currently makes (the Lexus IS). And that's one more than the number of cars I like in Honda's current line-up. So while I understand the appeal of Honda and Toyota to the hypothetical "average buyer," this is why I keep piping up when the overwhelming majority of this forum dog-piles on GM and holds Honda and Toyota up as God's two gifts to humankind.
