Yes, _Nepenthes_rajah_ is quite (not VERY) rare and endemic to
the Mt.Kinabalu of Borneo, but in the meanwhile in vitro cultures
of that species do exist, and the only reason for its high price is
that some guys want to make a big deal with it.
This species is quite illustrative for the great achievements of
CITES. Some guys with quite limited knowledge of botany or species
composition in certain genera (but with the more support from
their governement) sit together and decide which species is rare
or of commercial interest. They brainstorm for a while and then
write down some Latin names which come to their minds, and
call it the CITES appendix list. The two species listed for _Nepenthes_
could easily have been selected by a randomizing algorithm
without the need for human intelligence. _N.khasiana_ is maybe
one of the least threatened species of _Nepenthes_ on this planet!
Horticultural interest in this (quite boring and widespread in the
botanic gardens of the world) species is limited and easily saturable
by cultivated material.
While _N.rajah_ is much more thereatened, I suspect this was
chosen only because of pitcher size, as the other Mt.Kinabalu
endemics are threatened as well. And, whereas this quite well
known species growing in a protected nature reserve has not
suffered substantial decrease in the number of individuals,
some other species have vanished because of overcollecting
(_N.clipeata_ is extinct at its locus classicus--kind regards to our
German and Japanese colleagues!) or -even worse- because of clearing
of primary forest (the locus classicus of _N.neglecta_ is now farmland,
the locus classicus of _N.campanulata_ has burned after a dry period and
a consequent devastating fire).
IMHO, the only useful way to preserve threatened species is to propagate,
propagate, propagate. No endangered species list or any other piece of paper
has ever saved a single plant. If there is commercial interest, only increased
supply of cultivated material can destroy the market for wild collected
plants.
Kind regards
Jan