That's a surprisingly good point about what makes good radio, and well taken. However, I'd like to offer a counterpoint, and a rebuttal. Ha, I said rebuttal.
What happens when the time of day is no longer important? The Internet is global. I'm someone who goes between GMT-8 and GMT+1 on a regular basis. That's 9 hours of difference. Should we all keep zulu time for our playlists?
And what if we don't want to hear the "segues" and actually just listen to the music? My understanding is that commercial radio requires the chit-chat so that people can't just record the music. I've always resented it and it is a big part of the reason I don't listen to broadcast radio.
Finally, about "spontaneity". Again going on my unlikely-to-be-exactly-correct understanding, but isn't commercial radio the exact opposite of spontaneous?
Personally, I don't care about who brings it to me, but since I've left university, I really appreciate services that let me try and then buy (or not - I'm a paid monthly streaming subscriber) rather than being out of the economy entirely. I spent more last year in my streaming subscription than I had in the previous 5 years on CDs.
Maybe this type of service isn't so bad after all.
Just my opinion.