I pay $12 a month and only listen to one record three times through on that month. You'd expect the artist(s) of the record to get my $12 minus a service fee, but what I'm sure happens is the artist(s) only get the price per play x 3 and Spotify pocket the rest.
Subscription models are a huge boon for this reason, but the inequitable split might change artists' minds about these sub services.
I tend to listen to a small subset of music over and over, the artists should be getting close to that $12/month cost in my opinion.
I think companies like Spotify end up spending 60-70% of that $12 on paying license fees, which include per-play amounts that eventually end up with the artists. And the structure of those deals is such that the groups with the biggest licensing deals get most of your $12, even if you didn't listen to music from that particular artist.
I agree that it's not what you (or I) want, but it does make sense from the perspective of the largest parties involved in these negotiations.
I think your point is pretty valid though, if I listen to 6 hours a day I am contributing way more towards band payouts than someone who listens to a few songs a day, even though I am putting in the same amount. The direct connection could actually encourage people to subscribe, have a page showing your contributions to each band you listen to.
If the environment allows competition between distribution channels and artists are able to negotiate, artist compensation has the possibility to inch higher over time.
Case in point: Taylor Swift and Spotify. Regardless of whether her business model ultimately yields the highest return, at least she is not being compelled to distribute her material via Spotify.
I feel like Bandcamp (and iTunes) have a much better profit model. Offer full length samples so you know exactly what you are getting, and then charge 25-50 cents per track with 90% of it going to the creator. Despite the higher prices to the consumer, the cost feels a lot more justifiable in my mind. I've spent over $50 a month on Bandcamp before, whereas I can't see myself purchasing a music streaming service for anywhere near that cost.