Costs are always an issues that must be balanced. Two sports cars series could not be sustained in the US and now we have the Tudor(great racing). MX5 Playboy cup for sale? So regardless, the field size is a function of money. The NCs helped downward price pressure of NBs so we can afford to race them. NDs will do the same. But popularity in a grassroots series is do participation, no one is paying to see a miata race. Except me at the runoffs.
So Mazda's benefit is the halo statement that more Mazda's are raced any given weekend than any other mark. That elevates the brand, especially for the Mavens (marketing term for those who are early adopters and give advice to others). I am always praising the Miata and Mazda because of my involvement with SM and I know many do the same. If they go after pushing the newest model and lose the crowd that participates in SM, they have lost it all. I think it is too soon and after the runoffs to consider major changes to the series. I would be one more reason to be unsure about the future is another coffin nail.