Soundclouds problem was always that they started out as basically a free service for a particular niche(artist to label contacts), starting to charge(pissing off people who expected free forever) and then moving out of the niche made it so they never really had a footing for something people would pay for.

The problem with so many "internet unicorns" from the 2000-2010 era is that they handwaved per-customer costs as hardware/network costs and assumed that as long as they scaled then salaries would be a minor part, we as an industry are now trying to dig ourselves out of that hole with a even shittier AD experiences just as that AD market is crashing down.