Clearly, no commercial OS vendor can literally wait "forever" before releasing a product.
For that matter, non-commercial though they are in large part, even Linux distro vendors cannot wait "forever".
However, there's also clearly a difference between "waiting forever" and establishing an arbitrary deadline which has far less to do with technology and far more to do either with the size of someone's... erm, ego, or some kind of marketing timetable.
The honest truth is that the general public does not need any particular revision to any particular operating system. Companies need to release something so they have something to show on the books as of such-and-such a date. Now, I'm not trying to say a company should just not worry about ever recouping R&D costs, but they would be much better served (as would their customers) by taking the technologically correct amount of time to be sure what they want to recoup on is really ready to help them do that, not provide a further boat anchor for monies to be spent on further fixes on an already-deployed product, and the cloaked costs of customer frustration, only a portion of which shows up in the form of needless tech support calls and/or expenditures of store-level "Genius" scheduling.
And given the fact that Apple operates in the "sealed compartment" mode ubiquitous to most proprietary software development, it would behoove them in that respect as well to take their time, since they are unwilling to allow the sort of level of peer review which surrounds OSS-based offerings, particularly those more major projects, such as operating systems.
