I don't think I'm ever going to get over what.cd getting taken down. After it disappeared my new music discovery has plummeted.
The centralized private tracker model has a fatal flaw in that it's too easy to take down and all the work/hours people put in in curating and creating metadata ultimately wasted.
There are alternative models where the metadata is distributed but so far nothing has really caught on.
It's not so much because of the pirating that this service was successful, it's because of the dedicated userbase it held.
If something like what.cd integrated with something like Spotify- a legitimate way of accessing lots of music- say "here's a button to stream" somewhere on the site, it would probably be successful.
Mind you, one of the other reasons that these sorts of things with torrent or whatever backends get so popular is because there isn't a particular gatekeeper that can decide what can and can't be on the platform [1.] Destroying and damaging the effort of people who help your platform on their spare time tends to garner ill will.
[1] Spotify removing R. Kelly and XXXTentacion from their service: https://www.billboard.com/articles/business/8455549/new-spot...
The entire experience of what.cd was just amazing, and services like Spotify are lacking a lot. The situation is better than a few years ago, but still very far from perfect.