If you can supply a better version for less, then it’s a matter of finding a regional distributor that is willing to purchase them, the distribution in many regions is locked and if any of them fail as in collapse then, well anyone starting up subsequently after that, that be the old adage, repeating the same behavior and expecting different results.
It’s not a bubble that being the manufacturing side does not operate within one, they however are overly inflated and shrinking. They are connected to the markets and the markets are managed by others and they have set in place processes/networks/systems, they are controlling it as they should. That being there is no new buyers know that stage is over.
Basically your call is to outsource the labor to each hobbyist that has an interest in assembling their own motorcycle?
Also Zorge’s observation is astute, the Levis bikes were from primarily the same era as the Black Douglas, if any legacy is to be connected they should be based initially on that type of designs.