50 free accounts continually streaming music rack up 20 TB in a month. So that would take about 1.5 years. Our you use 750 accounts and do it in a month.
I would say it's weird they don't rate limit accounts but probably having a device play music pretty much all the time isn't even that rare of a use case.
You can probably just buy a thousand hacked spotify accounts for not much more than $1 a piece
That’s if they pretend to stream the music. If they are using throwaway free accounts I imagine they can download the DRM-stripped files much more quickly.