I agree with your sentiments.
However, I’m not sure this type of drastic action will work out quite as well as we would hope becoming more of a “death by a thousand cuts” rather than a cure for the problem.
Preferring evolution rather than revolution I believe the best way forward would be the formation of a “Super League” carved out of the best available riders making up a max of eight teams spread evenly across the country. Such teams/promotions committing to a clearly defined programme of continued improvement to the product on offer.
The remaining promotions would work to fixed (low) budgets to run semi professional events the purpose being to provide a basis for growth in riders ability and worth to the senior clubs.
Of course the biggest challenge the sport faces in the UK is the self serving, self preservation of individual promoters which exists to the detriment of our beloved sport. Frankly whilst that remains the case we can debate alternatives as much as we like but to no avail.
There is history of a sport bankrupt in its own right, on its knees and run by self serving owners with no future which is now so big it boasts the single richest annual sporting event held on the planet.
If anybody is interested in how that was achieved by the battles won by a single person against rich & powerful egos you should look up Pete Rozelle, who without there would be no NFL and no SuperBowl.