Watching the film again, I asked myself why I wrote that the final scenes are "problematical," go over the top, and raise questions they aren't prepared to answer. This time they worked for me, and had a greater impact. I began with the assumption that the skeletal silver figures are indeed androids, of a much advanced generation from David's. They too must be programmed to know, love, and serve Man. Let's assume such instructions would be embedded in their programming DNA. They now find themselves in a position analogous to David in his search for his Mommy. They are missing an element crucial to their function.
Here is how I now read the film: These new generation mechas are advanced enough to perceive that they cannot function with humans in the absence of humans. David is their only link to the human past. Whatever can be known about them, he is an invaluable source. In watching his 24 hours with Mommy, they observe him functioning at the top of his ability.
Now, perhaps, they can construct a mecha that they can love. They would play Mommy to their own Davids. And that mecha will love them. What does love mean in this context? No more, no less, than check, or mate, or π. That is the fate of Artificial Intelligence. A thinking machine cannot be understand except by something that is not a machine, and can think. David wants to be a real little boy. They want to be real mechas. No Mommy will ever, ever love them.
The "Trenton incident", mentioned in the movie, was revealed in the novelization. A homeless, drunk man was scanned with malfunctioning equipment and ripped apart on stage at the Flesh Fair, them thinking he was a mecha. This adds an extra element to the crowd's protests at the very life-like David being part of the Flesh Fair.
What happens to Teddy?
Let me get this straight... by the end David discovers that his model of child-robot is being mass-produced, so that childless couples can purchase their own David or Darla who will love them unconditionally, just like a real child. However, as has been pointed out elsewhere, nobody wants to take care of a child forever. Add to this the fact that apparently humans consider Mechas to be disposable, to be thrown away when they no longer serve their purpose or even when their human owners get tired of them. How many Davids and Darlas wound up abandoned and crying for their parents?