There are similarities, for me, of going to watch basketball in this country. I sometimes go on a Friday night and watch a game and it's a great night out. Lots of entertainment, good atmosphere (even family friendly), and competitive action.
I'd never really considered it when I first start attending, but I genuinely have zero reference as to how good/bad these players are. I'm aware that it isn't the NBA, but otherwise it could be anywhere between the level below that and Sunday League. My mates tell me that apparently there's better basketball in Eastern Europe but I'm not bothered, I just enjoy a good night out.
This is not to say that British Basketball hasn't had its own issues, they've had more than enough. However, the clubs have taken some of the good stuff that the NBA does and applied it to their own product at the level they're at.
The best route for British speedway to take is something very similar. Work out what's best for British speedway and go from there. As you say, nothing wrong with picking up some things Poland does, but we won't outmuscle them on virtually any level.
Obviously, the kicker with taking this approach is you'd need a solid plan, the right ideas, some joined up thinking and to get the word out there. None of which I'd have faith in the current set of promoters to do.