The App Store actually display a current size of 179 MB for Spotify.
But you're calculating it wrong. Very wrong.
Here's an example of a
47MB app:
https://apps.apple.com/app/ia-writer/id775737172
Yet when I update that through the App Store, it needs to download a
update package of merely
593KB to update the last to the latest version:
View attachment 2325009
Thanks to the clever use of app update packages (that you may want
to read up on), the update size is reduced to - in this case - a small fraction of less than 1.5% of the full download.
This was the first and random example showing up in my App Store updates, and admittedly, this must have been a small code update without updates to other app resources (images). But Organic Maps is also displaying 623KB update on a 115MB full download app - so not an extreme outlier.
EDIT:
60 Petabytes is approximately 60 million Gigabytes.
Your $3 million per month figures assumes a cost of $0.05 per Gigabyte.
Some
quick googling convinces me that it actually must be less than one cent per GB, at Apple's size.
Given your assumptions about number of users and app downloads and mine about size, that'd make for less than $10k a month (on small updates).
👉🏻 That’s a bit less than Tim Cook’s 2022
hourly executive compensation (almost $100 million for the year. Or more than 10k per living hour - basically assuming the guy doesn’t sleep but works 24h a day).
Again, that’s just assuming small code updates - but anyway, it’s a fraction of your estimate.