This isn't even an audio thing. With a classic television, you can crank the channel dial and (along with the instant audio output) see a stable frame within 5-20 frames of vsync (so like 300ms or so worst case).
My TV at home can't switch an input (e.g. between two HDMI inputs) faster than about 3-4 seconds. No, I don't know why either. It's actually much worse if the device being switched away from is a Chromecast. Don't know why there either.
https://www.synopsys.com/designware-ip/technical-bulletin/hd...
Of course, in the time it takes for my television to initiate a secure transaction channel with the input hardware on the other side of the cable, my ?!%!? Netflix app has done a arguably more secure transaction with a server on the other side of the continent. Sigh.
> I can send an IP packet to Europe faster than I can send a pixel to the screen. How f’d up is that?
John Carmack
https://twitter.com/id_aa_carmack/status/193480622533120001?...
Hardcoded "everything is NTSC" vs a mutual handshake/negotiation and mode change makes sense, though I too wish it was much faster.