I'm also greatly disappointed that they seem to have settled on 128kbit MP3 as the peak of quality.
So they were in a bit of a chicken and egg situation - they needed to monetise the service but couldn't because they weren't legally able to, and to compound this they were sitting on a liability because technically they had been infringing the copyright of songwriters - but to do a deal to be legally able to monetise they had to be able to generate some sort of revenue stream to be able to get forward investment to settle the terms of that negotiation.
TL;DR - Soundcloud couldn't charge people without potentially being sued at some point about a copyright issue. To be able to charge people they needed to settle that problem and it seems like that all went on too long and now maybe they've hit a point where the model for monetising soundcloud isn't working as fast as they hoped.
Essentially I want to pay them something to be able to listen to SoundCloud's uploaded tracks on my phone offline. That's it! Until they can compete with Spotify on a technical front and make me switch, I can't justify the $10/month, but I can certainly justify paying less for a sliver of that offering.