FWIW, Mazda has a multi-tier racing program, culminating in Pro rides via StarMazda, USF2000, Indy Lights, and connections to Indy Car.
http://www.starmazda.com/about/series
The lower ranks of SpecMiata & MX5 Cup are used by Mazda for recruiting. So some folks go all out in the hopes of earning a ride/sponsorship.
But I agree, the rules appear to be in need of some re-assessment. It doesn't make sense to have such variability in a "spec" series. I heard from a friend of mine that did SM briefly, that Mazda (MazdaSpeed?) would sell racers a "stock" motor for around $2,500. For "serious" interests there were "pro" motors out there for around $7,000. And IIRC, they were supposed to be "sealed" motors. The idea that premier engines are now going for 4X that much is insane. Recalls for me the days of SCCA Showroom Stock, where dealerships were building "ringer" engines by scouring the parts bins (literally thousands of parts...) for weight-matching engine parts (cranks, connecting rods, pistons, etc) to build a "blue print" motor withough doing any machining. Not possible for the backyard entrant.
Kudos to Jim Drago for taking responsibility. But this also illustrates how rules are important, and people should stop bellyaching when rules get to be too lengthy. Vagaries will always be exploited; sometimes it helps the sport, but not always.