Unless you go for the overpriced maintenance hogs (audi, volvo, VW, etc), cars today are as reliable as ever, although they are also much more complicated. Honda and toyota are still a cut above the rest in terms of reliability, bang for the buck, and mechanical quality (maybe not the auto's, hah). If you look at the newer, more delicate paint processes (also friendlier to environment) as a bad thing, then sure, there's one thing. There are also a few minor rattles in the newest generation, but I've driven some absolutely horrible cars in terms of reliability and quality that were very, very rattle free, so I don't think that's a good way to really judge quality or the meat of a car. Mechanically, however, the only other company that I would really trust as much as Honda is Toyota. The thing that seems to plague cars today, however, seems mainly to be petty electronic problems in overcomplicated radios, nav's, climate controls, etc all mashed into one much of the time. When something went wrong with any of that before, it was generally a relatively inexpensive thing to fix, not so with many recent vehicles. More often than not in cars that I have owned (or my family), I have had to replace a head unit because the factory unit failed or was on the way out, but that option seems to be going the way of the dinosaur sadly. As far as cost efficiency and manufacturing, that has always been and always will be a factor. Make as much money as you can while spending as little as you can to produce the product. Outside of (some) charities, good luck finding one that doesn't lean in this direction to some extent.
As for americanized hondas, I think that is more due to the fact that pretty much EVERYTHING is a little more high-tech than it was in 1989 (and obviously more high-tech in 89 than it was in 70, etc). The differences between an 89 accord and an 06 accord seem to fit right in with that idea, at least to me. As for size, the civic is still a tiny car, though the accord seems to have grown significantly since I owned my 95. I assume this was simply to further differentiate the two models to attract a larger overall consumer base.