The "limited edition" backer benefits are either the Consultation-- which requires considerable effort-- or the ones with the dice.
As for damaging the company, with the exception of the core books I suspect that the price of producing each of the stretch goals was built into the stretch goals themselves, so at worst they're simply making the vast majority of their money up front. It's a sound business model-- you only produce what the customers want, and you make all of your money up front, so everything you sell after the funding campaign is over is long tail profit.