While some of the ideas are solid, I think the original topic is off-kilter. First off, a lot of beginners want a smaller camera, by taking the AF motor out, you save size and weight. Secondly, if someone does get really interested in photography, when its time to upgrade, they will buy something better, and the best part is, they will be able to use every lens they already own. Next, most of the target market for the D40 isn't interested in lugging around 15 lenses. Most purchasers bought it because it was lightweight, and easy to use, not because it was "pro-model durable." Do you seriously think most beginners are going to carry 8 specialty lenses around with them? No, most will likely carry the kit lens and an intermediate zoom, and nothing else. Furthermore, most of the target market want to push the shutter-release and take a picture, not fiddle with DOF, or bracketing, or things more advanced users enjoy. Another problem with this argument is, if someone goes out and uses the D40 like a pro, how long will it last? I wouldn't bet on it being very long.
The major problem I have with this argument is, sabbath, you aren't looking at this like the majority of potential D40 buyers, you are looking at it from the perspective of someone who is very interested in photography. To us (those very interested in photography) lens useability is important, but to a begineer, who doesn't have a stockpile of glass, it isn't nearly as important. Most people whio buy a D40 will never be able to tell you the extolls of a "thrifty fifty." Most probably won't even know it exists unless a friend mentions it. Sure it would be nice to have "cheap" lenses available, but I don't think most D40 buyers care beyond a couple of "cheap" zooms.
I think Nikon did an excellent job with the D40, and we should try to get as many D40s into hands as possible. Why, you ask? Because these people are people who probably would never have taken an interest in photography before buying the D40, and the more people we can bring into our hobby the better it is for all of us. If they decide to upgrade one day, then it worked on many, many levels and is benificial to everyone from the manufacturers, to artists, to the hobbyists, and to the pros.
I've got a friend who owns a D40 and absolutely loves it. In a few years he may upgrade, but he may not, its too early to tell right now. I'm working extremely hard to turn him into a photographer as opposed to a snapshot "artist." One day he might catch the fever, but if he doesn't, he still enjoys his camera, and that is the most important part. Remember the technical apect of the thing is unimportant, its all about making great photos and the D40 can make great photos. People used MF lenses for years, people used lightmeters and grayscales for years, people used manual winding for years and yet they still took great photos.