R&D is often the least sexy part of things. It only looks good when the job is done. CARB cert involves even more R&D than you already did to make the product in the first place. It can easily surpass the development budget. You have to give CARB 3 vehicles with 3 of whatever you made and prove that they all do equal or better than factory emissions.
States have adopted their own CARB style of emissions checks and laws, but the California board is not meddling in those other states. Some states fail you if there is any CEL, others don't care as long as the tailpipe is clean. IM240 dyno testing is a few steps above a tailpipe sniff at idle. I believe it's worth it to go for CARB cert. If it'll pass CARB regs, then it'll pass anywhere. CARB cert is also a bit of bragging rights.
Ever see a sexy model getting ready for her show? The process is tedious, time-consuming, detail oriented, and procedural to get her to look that good. When the show is over, all of that prep comes off. That's analagous to SEMA show prep.
All of the prep work and R&D has to stay and last for years and years on all of these systems.
Consider a 15-25 year lifespan for parts, too. Racers will always blow stuff up. That's what we do
. Who blows up the least, wins :p. What impresses me about all of these systems is that you really can leave them alone and they perform fine. You don't have to change plugs for highway use, or re-jet, or pull over and let it cool off on long trips. Users have more demands nowadays. CARB is just part of that picture.
/rant