Promotion is an expensive business especially in your first 2 or 3 years as you build up your assets, hopefully the brummies promotion was wise enough to budget for that and can survive their first season.
Re the support in Birmingham, yes i think there is but the Brummies problem is the stadium. it's a very expensive place to promote and an expensive place to watch with speedway always treated like a 2nd class citizen. The first promotion was bankrolled by the ex-Worky promoter Tony Mole who had very deep pockets.