Apple has always chosen form over function, and this isn't any exception; the aesthetics of a "clean" boot process is clearly more important to them than being able to easily figure out what's happening, and I suspect at least part of the reason for this opaqueness is to encourage learned helplessness and visits to the Apple Store (which may result in upselling or otherwise exchange of $$$) when something doesn't work.
Personally, I very much like the detailed and informative POST screens that older PCs default to, and indeed the whole audiovisual experience[1] of the boot process. It's far more reassuring to see things happening than pressing the power button and being "left in the dark" waiting at a black screen for a few tense moments as something happens.
[1] The satisfying "clunk" of the power switch, to the fans and hard drives spinning up, the latter doing their initial seeks once they've reached full speed, the beep of the POST, the buzzing of the memory test, and then the sounds of the disks loading the OS. It's all very information-rich, and once you get used to the normal routine, it's easy to notice when something changes unexpectedly.
Personally, I very much like the detailed and informative POST screens that older PCs default to, and indeed the whole audiovisual experience[1] of the boot process. It's far more reassuring to see things happening than pressing the power button and being "left in the dark" waiting at a black screen for a few tense moments as something happens.
[1] The satisfying "clunk" of the power switch, to the fans and hard drives spinning up, the latter doing their initial seeks once they've reached full speed, the beep of the POST, the buzzing of the memory test, and then the sounds of the disks loading the OS. It's all very information-rich, and once you get used to the normal routine, it's easy to notice when something changes unexpectedly.