Agreed, and the solution is painfully obvious: Show the item once in the feed and just let me know that "DJ Joe Doe, Awesome Records, [guy who is in my network] and 27 other people reposted this."
Come to think about it, isn't that how most other social feeds handle this problem?
Facebook has been doing this for years and it works great. The duplicated content is shown once, and then the separate comment feeds from the different reposts (if there are any) are put below it. Soundcloud wouldn't even have to innovate here; they just need to copy what's already working elsewhere.
Not having duplication is better for revenue because having duplicate content fill up your feed because lots of your friends re-shared something is bad UI. I'm not really that much more likely to click on something after the first time I'm shown something, and I start to get actively pissed off at it after a few unnecessary repetitions (this was a big complaint about the spam coming from Facebook games in the early days). Spamming up the feed with duplicate content means that for the same time spent browsing, someone sees fewer pieces of original content, meaning their average click rate is less, and yes, that costs revenue.
But fundamentally duplication costs revenue because it's a bad UI and bad UIs piss off users, leading them to use your product less.
Come to think about it, isn't that how most other social feeds handle this problem?