Aviv Hod wrote:
It seems that the ubiquity of models in kid's bedrooms might be
threatened by manufacturer's demands for royalties for the intellectual
property.


The same intellectual property rights that protect the original designs
also apply to the kits themselves. If manufacturer A were to start selling
model airplane kits that were reverse-engineered copies of manufacturer
B's kits, I'm sure B would not hesitate to cry foul and run to the lawyers.

If kit manufacturers don't want to pay to use the fruits of someone else's
labor ("one and one half percent of anticipated profits" to quote the
first cited web site), they are certainly free to create their own
original aircraft, auto, and train designs.