I don't think the issue artists have is what the record labels are making from Spotify, but rather what they're making.
I only mentioned the record label because independent Galaxie 500 gets 100% of Spotify's payout, while Katy Perry (the person) presumably only gets a small fraction of Spotify's payout. And it's Spotify's payout that's relevant to the discussion, not the money that the artist ends up receiving.
This comment seems to suggest that if more people listened to the music of these indie bands, than they wouldn't be "whining" about the Spotify model. However, given that best selling artist in the country also feels she's being ripped off by Spotify and pulled her music from their service, the discontent doesn't seem to be limited to niche artists.
Taylor Swift is just making a smart business decision, and essentially "ripping off" her fans in the process. I'm sure she was quite happy with the $6M/year she was on-track to receive from Spotify, but just realized should could (temporarily) make even MORE money by forcing her fans to make purchases instead.
Streaming and sales essentially provide the same amount of revenue over the long run. The difference is that with sales, all the revenue is recognized up-front, at the point of sale, while with streaming, it trickles in slowly over many years. Obviously money "now" is more exciting for artists, so by keeping a new release off Spotify, it pushes people to buy the music instead and deliver all the money up-front.
But making that up-front investment is a gamble for fans. If a fan listens to a purchased song more than 150 times in their life, then the fan "wins", and buying was the right decision. But for every fan who listens less than 150 times, Taylor Swift wins. So keeping an album off Spotify is a way for an artist to push more-casual fans into making the "purchase" gamble, most of whom will "lose", while the artist cashes the check.
So delaying a Spotify release has become a bit of a trend. Eric Church's 'The Outsiders' (a pretty kick-ass country/almost-metal album) is one I'm aware of. They knew it was highly-anticipated (it ended up hitting #1 on the Billboard 200), so they chose to collect as many sales as they could, and then, after a few months (presumably after the sales volume began drying up) they released it on Spotify so that they could collect the long-term revenue there as well.
Taylor Swift's case is a bit different, as she removed her back-catalog in addition to her new release, but I think that's easily explained: 1) She's so huge, and like 'Dark Side of the Moon' still selling tons of copies every year, she figured her back-catalog still had good sales-potential. And she was correct: her albums had remained in the Top 200 for years after their release, and in the week of '1989's release,
her 3 previous albums re-entered the Top 200. And 2) removing all her albums allowed her to present a more-principled and wholesome-seeming "it's all about the value of music" rationalization to her fans vs. an "it's all about more money for me".
So I wouldn't be at all shocked if in a few months to a year, we see a "deal" whereby her albums return to Spotify, because as the new-release sales start drying up, that extra $6M/year will start looking awful sweet again.