Perhaps, but a cheap and sturdy plain old IKEA desk with a wooden desktop costs about that much.
This is difficult to believe, given that new cheap office/task chairs start at that price. Do you have a link?
They probably wouldn't make a good drop-in replacement for office chairs since they aren't on wheels. On the other hand, footrests are nice...
To be clear, the IKEA table is probably made of a composite wood, not a proper slab of wood, but I agree with your point. Material cost should not dominate the price of a desk.
To be honest though, I think the value of a motorized desk is being overblown. I have just put my desk up on 4 stacks of office paper in the past; worked great. Everyone needs new expensive toys though...