This makes no sense. This thread clearly states that there's a Beta 6 but it's not being seeded, it's just not being seeded to all of the developers like the previous betas.
This build has an obvious focus on allowing Carriers test network related updates/enhancements. Which makes sense, but would not really be intended for testing general stability and functionality of the software/devices in all scenarios that a broader test bed would offer.
Apple only releases betas to developers so they can begin enhancing their apps for the new version of iOS.
While they do allow developers to submit bug reports, that is not the main objective of releasing betas. Apple issues much more frequent internal betas that are used to work through all of the issues during development. The last beta we received was probably already several weeks old at the time it was released to developers. Even the new beta pushed to carriers is likely several weeks old. Apple's internal testing is much further ahead, and will be ready for GM release in a few weeks time.
Seriously? There are likely builds every night, maybe multiple builds per day.
I do happen to know that internally (and possibly in a limited external basis) that Apple has more frequent builds than just the betas released to devs. I never indicated that Apple didn't have more internal builds. But honestly such a limited subset of people are less likely to come accross the issues and bugs that a larger audience will. Furthermore, feedback through dev channels helps Apple to prioritize better based on actual broad real-world usage of the device/software. More builds released, more feedback, and more time spent testing, gathering feedback, fixing bugs and enhancing functionality is beneficial to everyone, it benefits Apple, the Devs, and ultimately the folks that really matter... the end users.