To paraphrase the old racing line: Quality costs money. How much quality do you want to buy?
Any oem has the resources and abilities to create an extremely high quality car, in my opinion. It is a matter of hiring the best people, specifying the highest quality supplier parts, designing the best factory and filling it with the best equipment - and spending a great deal on product testing.
I've always though GM, with the enormous resources it had, should have been one of the world's great companies. Unfortunately it made the tactical error of putting too much money into shareholders' and management's pockets, instead of into product quality (and other product areas, too). Now it seems they may have gotten the message, but also that it might have been too late.
Some smaller manufacturers, to make an exciting product, have to put so much of their resources into design and engineering that there is simply a limited amount to keep the quality at top levels - I'm thinking BMW here, and I think that is also the approach Nissan has taken, with Renault's help. In both cases it has led to lots of exciting products but increasing imperfections in quality.
Some are just too small to compete in a super-competitive market. They become "niche" manufacturers, and some don't survive or get eaten up.
Toyota is in an enviable position. They have built an enormous infrastructure of quality, and are now set to surpass GM as the biggest in the world, too. They will be very difficult to compete with. They also have a relatively concentrated product line, with an efficient approach to the sharing of hardware between lines and brands.
One really interesting exception is Porsche. Very small, but also very high recently in every standard of quality.
As for Honda, I can see that they might be getting squeezed a little. They were very late to the SUV/Truck party, which Toyota certainly was not. They have the disadvantage of the domestic Japanese economic malaise, which the Americans/Euros don't, and at the same time there is almost a revolution underway in the car market in general - in styling, versatility, performance, and variety - which has to pressure R&D costs upwards. I can see how things might be more difficult for Honda, right now, than Toyota - but it looks like they are executing very, very well.