There's probably some people who aren't familiar at all with trikes, but want to jump on the bandwagon and have more money than sense. They overpay and try to pass that gift on, when along comes another person with the same affliction.
Most of this is driving personal profit, for whole machines and
parts. It's not causing a huge resurgence in aftermarket support, it's not really spreading the money around to create new businesses or drastically increase profits for existing ones. There are some die-hards who love doing it for a hobby and make small runs of
parts and accessories. They typically got into it all when these were still available new and resources were more readily available, as well as potential sales. These people eventually die out and very few are picking up the torch.
There are some group buys for special
parts production, but that's not very often and usually takes a good bit of time to put together enough confirmed sales to make it happen. If it happens once, and you miss out, that's the one shot you had.
The OEM
parts availability is all but dried up. 200X kicker gears anyone? It's NOS and vintage aftermarket at this point.
Restomod? Modern engines stuffed into old frames? They're only original once.
Maybe it all is driving some market, the conversion market, where modern dirt bikes and quads are turned into trikes. If I had the disposable income, I'd be looking in that direction more than a 30 year old machine with very limited
parts availability and having something I'd really not want to beat on for fear of damaging it. Riding off road while having to worry about damage? Yeah, right.

Riding a 250R around the yard or the cul-de-sac in a suburban paradise so it doesn't get dirty or hurt because you paid $5,000+ for it...may as well learn to enjoy riding a electric scooter.
I'm just being a sour puss, but anything I have, I'm going to ride the crap out of it. Not abuse it, but there's a good chance it'll get banged up at some point. My body isn't going to be museum quality once I'm done with it, why should anything I own after I'm not able to enjoy it. Livin' La Vida Loca!

Take this trike and shove it, it ain't running here no more
Imagine dying and leaving behind a pristine machine you hardly rode...did you actually live?
Tuesday morning and I'm doom glooming. Oh yeah, it's going to be a rainy week (raining outside right now and FedEx just dropped off some new trike tires). Haven't even had my morning Monster yet. Time to kick the tires and...put them on.
Triker for life, or at least until they get too expensive, then I'll buy my first quad. Peace.