This is an old-ish post now, but …
If I was planning an interview about using AP for federating music services, I’d reach out to some of the people here experimenting with it. @petitminion and the FunkWhale team have been doing that for the longest AFAIK. But I think it’s fair to say their focus has been more on software for running a music library than a music store? @bandwagon was set up to be music store software federating over AP (did you know about FunkWhale when you got started Ben?), and has been around a couple of years now. The @mirlo team have been adding federation features to their software, which was initially built for running standalone music stores (I think?), and using AP for some of those features. Any of them would have valuable experiences to share, if they’re willing 
For sure. IA use the same donation-funded NGO model that’s worked sustainably for Wikipedia and a handful of others big commons projects. But they only work because of a deeper layer of interop protocols that underly the web and the net (HTTP, TCP/IP etc), and on top of those, they make heavy use of RSS and BitTorrent. So even in that rather centralised platform, interop over open standards has been a big focus.
IA folks have been active in the fediverse, and decentralised social network development more generally. They’re painfully aware of the risks of having such a big pool of the net’s history (the WayBack Machine web archive, huge music and video archives, etc) dependent on the health of a SPoF, and they’ve led a lot of discussions about how to make the IA more decentralised.
The Free Music Archive are another example of an org that tried to follow the Wikipedia model. It didn’t really work as well, and it was almost shut down due to a shortage of funds. Then ended up getting sold to a startup called KitSplit, and then to Tribe of Noise in 2019. No idea how that’s worked out for them, but the site’s still there, so I guess it’s going ok for now.
So I the IA’s current model as a lucky exception, with question marks over its long term sustainability in its current form. I don’t know that any of the projects represented here would see a donation-funded NGO as a reliable way to fund their work (please correct me on this!).