Why Public Betas?

They're to stop non-developers installing developer testing builds that'll break their devices. Put out nearly the same stuff, on a delay long enough to have a little confidence in it.

He says "operating systems" but only mentions iOS. Assuming Mac OS X is included as well, I was involved in testing via AppleSeed from 10.2.1 or so up through 10.7 (all major and minor releases, as well as security updates). It was a really neat program with a fairly small number of dedicated testers, and we'd get occasional feedback directly from engineering, or Apple staff would (rarely) post on the forums. At the end, we'd get the GM build and a t-shirt (or in the case of Snow Leopard, a hooded sweatshirt), as a thank-you. Some of the old-timers who had been part of Apple's CQF program said the swag was better in those days, but it was a nice gesture after sacrificing data to a FileVault bug.

In fact, 10.6.8 was the last OS that I really tested, because I had problems with the 10.7 installer, and Apple never responded to my bug report on it. I think that's when they opened seeding up to the public, or maybe just a huge group of beta testers. Anyway, when the program got big, I stopped getting responses to bug reports, and Apple started in with this Feedback Assistant bondage-and-discipline routine of uploading a sysdiagnose. It felt like we were just uploading data to juice some department's "metrics" and statistics rather than helping fix bugs that affected users. My assumption is that it's only gotten worse.

I haven't been beta testing Apple OSes as long as Adam above, but I did it long enough to notice a definite pattern where Apple responded much more to beta bug reports 5+ years ago than they do now. I mean like actual responses where a real person replies asking for more info, or telling you that they're working on it, or to check to see if it's fixed in the newest beta version, etc. Last year during the iOS 13 and Catalina betas, more than 80% of the bugs I reported didn't even get marked as Duplicated -- there was no acknowledgement whatsoever. The other ones were super obvious show-stopper issues that I figured they would fix whether I reported it or not. I will never again waste my time filing bug reports with Apple.

Which raises the question: what is the point of the public beta program? Is it really intended to improve the quality of the released version? If so, why do we keep hearing of bugs that are reported but persist throughout the beta cycle? Whatever its original purpose, the public beta program is now a marketing tool—a way to get Apple enthusiasts hyped about the new releases and hyped to buy the new products that come out alongside the new software.

Ehh. Maybe that’s part of it.

But that hype was already there. When there was no public beta (only developer betas and AppleSeed), people were buying developer accounts just to get that beta, then reselling UUID slots on those accounts. So the demand was clearly there, though perhaps more niche.

You also can’t extrapolate from “iOS 13 shipped despite a ton of feedback about quality issues” that the feedback was worthless. You can speculate that, for example:

it wasn’t actionable enough (e.g., bugs were hard to reproduce)
the schedule was too tight

But that doesn’t mean Apple should gather less feedback.

(Should we test less for COVID just because we have a hard time fighting the virus?)