> the calculus has changed in favour of power savings and against flexibility

This has always been a trade-off. For instance even with desktops, once video handling became common we first had video decode/encode being handled by GPU acceleration. But now most CPUs include dedicated h264 (and more recently hevc) decode/encode support, eg [0].

Although it's much lower computation, hardware acceleration is also offered for audio, and I'd take a guess the reason the Apple APIs for checking which hardware supports hardware-based audio encode/decode [1] has been deprecated is now because all supported devices provide all possible capabilities.

[0]: https://en.wikipedia.org/wiki/Intel_Quick_Sync_Video [1]: https://developer.apple.com/documentation/audiotoolbox/16204...