I agree we're not very far apart at all and there is no magic bullet that is going to cure all of Speedway's current ills, at the moment it's a death by a thousand cuts. I do take onboard what you're saying about participation, but there are avenues into the sport but that's not to say that more couldn't be done, you can always do more with everything and things should always be under constant evaluation.
One thing I will say about Speedway is that it's niche, especially as a participation sport, always has been always will be. You can't just go into a Sports Direct and by a set of Darts, a Cricket Bat, Tennis/Squash/Badminton Racket, Golf Club, Hockey Stick, Football, Fishing Rod, Tiddlywinks etc. You have to go to a specialised supplier and buy highly specialised kit and I dare say you'd have done your £3k before you got anywhere near a Speedway track. In this respect it is also similar to F1 or more specifically Single Seater racing. Even the motorcycling fraternity don't really buy into Speedway like they do with MotoGP & Superbikes, I've heard it said that it's because they can go and buy the equivalent bike and ride it on the road and/or track.
Can't argue with most of your last paragraph, I do think there will still be team Speedway in the UK in 5 years time though, even if it's only at an NDL level.
All the best
Iain