As someone who has been in the distribution business for over 40 years and now teaches business and finance i believe our hobby follows basic business law.
Commodity products (mass produced or large production runs) will rarely increase in value. Limited editions and custom built items (e.g small dioramas and buildings) will fetch premiums over time.
Certain makers get hot because a small population of avid collectors bid up the value. Right now, for example, Trophy Miniatures which ceased production about seven or eight years ago seem to be getting decent premiums.
Especially their rarer items such as boats, vehicles and artillery can be bid up by just a few zealous buyers. Trophy, as others, also is a quality product that bridged the gap from older style gloss to better sculpted and painted precursors of the matt types. So there are makers with historical and innovative significance to our hobby that will hold their value as well.
If prices continue to go up exponentially and the hobby doesn't implode you can probably sell your most recent acquisitions for around cost.
Unlike what I call investment hobbies such as stamps, coins, sports memorobilia, certain antiques and art. Our hobby is more hands on, visual, creative and "fun" (I would say another example of a fun hobby are toy trains).
If you are collecting for investment buy limited editions, discontinued items, out of business makers and rare older pieces. Like any business you have to research the market, understand the trends and the macro-economy. Down the road I think "trading" will become more popular as well.
And always remember that if you enjoy collecting, painting, diorama making, art and history.....you can't put a price on happiness! Happy people live longer.
