Increase.
They're probably close to rock bottom right now. They look cool and of limited supply. That usually portends to good value retention for vehicles in nice condition. Also, depending how well electric vehicles are received, they might prove to be good vehicles to convert to electric. They are large enough to easily stow batteries and have the GM bellhousing ...and newer (and better) electric conversion kits will be coming online in the future. Once electric vehicle technology goes through several technology revisions, and people have greater familiarity with electrics, electric conversions on older vehicles will likely become commonplace. At the same time, fewer and fewer people will have less knowledge of engines (that's probably beyond 10 years).
Then again, 1) the west could be at war with China (at least a trade war) which disrupts trade and chips for a dozen years, 2) the U.S. could have it's own civil war in which interstate grids become a weapon (or vulnerability), 3) the Ruski's, Chinese, Koreans or Iranians might succesfully take down a large part of our electric grid as an attack (leaving millions of electric vehicle owners drivers stranded w/o reliable power for weeks ...souring the switch-over to electric vehicles), 4) hydrogen technology might surge ahead. 5) H3's never really catch on for a variety of reasons and remain a curiousity, like International Scouts. I would say, at least one of the above (if not two) are likely. So who knows?? There was a time when a guy could buy a '73 Camaro and Bandit Trans Am's really cheap. And those first Gen 22R Toyota pickups (I owned several of those) ...they've gone sky high. I would think H3's will eventually be like that. Pickup and Alphas even moreso bc most of the 5-cyl engines will have crapped out and there aren't cheap replacements out there.
"...difficult to see, the future is".
