using a Speedway analogy - the dog has to come from the right stock (bike/engine manufacturer) and the better ones cost more.You need the right kennells (workshop) and training (tuning) and food/consumables (fuel/tyres) again the best cost more.
If crowds are falling and costs are rising (applicable to both) then thats why less breed/compete (buy bike/race) which means fewer tracks are viable (applicable to both)
Just breeding a few mongrels wouldnt automatically mean more tracks are viable.