Are you attempting to intimate that the D50 isn't a consumer camera? That's specious. The D40 and D60 cameras are a complete replacement for a D50 in their target markets. Nikon understands the market they're in and they understand how to make successful products for that market. In fact, since the introduction of the D40, Nikon has picked up significant market share
You are correct. The "target market" typically buys acamera based on price then shoots about 200 pictures a year. All of them in "full auto" mode.
Even people here who ask all kinds of questions will in the end buy based on price. Giventhe the D40 is the lowest priced SLR or cource it sells well.
That said the D40 does what most people need and has a fair price and works well in fully auto mode.
How many images can you soot before the shutter fails? At 200 images per year or even at 1,000 per year most people will replace the camera LONG before it fails. Even the D50 with a 20K shutter life is "good enough" for
Think of a DSLR as a pack of film. It is a "consumable". Use it then buy more. No one would keep and use a DSLR for 20 years. What do you think a D300 will be worth in Feb of 2028? Would you even care if the shutter worked?