Why should it be variable, if we talk about digital media? Storage and content streaming is cheaper than embracing a whole logistic (producing DVDs/BlueRays, packaging, shipping).
But here we are again: if you buy something digital, you just pay for a "usage license", you don't own anything at all. After all these years or decades, I am still surprised that people expect to own digital content, forever
Well, that's how it's sold. The buttons say something like "Rent"/"Buy" not "Short Term Rental"/"Indeterminate Term Rental".
To be an internet consumer you have to have some level of confidence in the good faith of the seller, including that the basic description of what's being sold is accurate. Otherwise, you wouldn't consider sending your money at all. Probably most people see "Sony" and trust that brand not to scam them.
But so as much anymore.
It could even incentivize actors to consider other options, like selling access to download the files themselves
Not necessarily. What if the store didn't have to do that?
That's fair so long as it was made clear at the time of purchase that you aren't buying the song, and that you're only renting it for a while. If they didn't put a clear explanation that you might lose access on the page when you clicked buy, and not buried deep in a 50 page EULA, then it is entirely reasonable to assume that Apple can afford to keep a 5MB file available for streaming forever, or until Apple closes down its streaming services.
But like so many other comments here state: it's very much a known fact that 'buying' something like this is just renting it for a short time period. We must keep fighting for them to actually state this in bold text before you pay them.