Interesting topic.
I too try to support my hobby by looking for items that can be resold at a higher price. Funny enough, I have had great success with limited run "S" gauge items offered by NETCA and have on order some "S" gauge cars from METCA. I look for limited runs that I think will appeal to a large audience.
I do this with some "O" gauge items as well by purchasing SELECT items from LOTS, LCCA, TTOS and other groups. If this offends some people it is unfortunate, but I can't be concerned.
Paul