Things have shifted; and the generation (and the +/- 30 years that bracket it) that drove our American gas-powered car and moto culture (which fueled competitive racing) is passing. Probably happening in other markets as well.
Consider that the latest sportbike market, which at the top (1000cc) was being driven by boomers and at the bottom (600cc) by easy credit to younger people, has apparently (or at least somewhat) collapsed. So the manufacturers probably have less interest incurring the expense of racing in a national series.
Now the boomers (many of whom can't fit comfortably onto sportbikes anymore
) are moving into cruisers, nakeds, and adventure bikes; and the younger folks seem to be more interested in (relatively) cheap/utilitarian and "cool looking" (which is always subject to change and being directed) bikes.
I suspect there will always be a market for sportbikes/racereps, but probably no where near the volume in the past which fueled all the race activity it did.
So maybe we need a race series that reflect that changing set of facts. It might be far-fetched to imagine a 1800cc cruiser race series (would be fun to watch though), but a naked class (i.e., no clipons or side bodywork) would be reasonable.
But, otoh, sometimes they come full circle. Motorcycling was in a real funk at the end of the 70's and early 80's. Then it got spectacular and remained so for 20 years. So let's hope for the best (and buy a new bike this year!).