The lack of control over hardware and software on contemporary Macs is a show-stopper for me. Once they get back to Snow Leopard ideology I'll return, until then it's Linux or Windows for me
Snow Leopard dropped the price of the update from $129 to $29. This might have been part of its positive reception.
Apple’s design philosophy isn’t particularly different from that time. Snow Leopard was something of a feature freeze to make up for deficiencies with Leopard.
Apple was never some pariah of hardware and software flexibility. If you had a PowerPC Mac or older you dealt with all kinds of incompatibilities from different peripherals, floppy disk formats, and physical connectors.
The interoperability of Macs is the best it’s ever been, especially since Apple no longer deals with a <5% market share like the 1990s.
Could that be an indication that users don't really want new features in their OS?
I don't think enough people appreciate just how beautifully hackable OS X used to be. The Library folder was unhidden by default, basically inviting users to go explore their systems. Applescript and Automator were treated as first-class citizens, offering an easy way to extend existing apps. Custom themes—while never officially supported—were easy to make via a bit of file replacement, and there seems to have been quite a lot of them, if DeviantArt is any indication. And there was nothing to stop you from writing and loading your own drivers to add support for new hardware, as plenty of enthusiasts did.
Today, stock apps like Music store data in obtuse and non-human-readable locations, Apple Events are virtually useless due to mandatory permission dialogs, kernel extensions are deprecated, and the root filesystem is mounted via a complex snapshot mechanism in which a reboot is required for changes to take effect.
Perhaps this was always Apple's goal. Perhaps it was necessary for security. Perhaps, for a majority of users, it ultimately provides a better experience. But if you are someone who likes to tweak and customize your machine, OS X used to be a great home, in a way that it isn't today.
I won’t address your whole comment but I feel compelled to point out that Music is iTunes. The Music app was just a name change, and, confusingly, Apple Music (the service) is an entirely different entity than Music (the app). Your own local music files (either your own MP3s or iTunes Store purchases) are still accessed in the same iTunes Media Library folder as they always were.
Music was just a rebrand, and it spun out podcast, audiobook, and iPhone/iPod sync. But the rest of it is 100% iTunes.