It's worth noting that other fields take a radically different perspective on this. You can see Brandon Sanderson talking about how software developers get such great deals from publishers, with Apple, Google, and Steam taking puny 30% commissions, and he wishes authors could get something similar.
The 30% number was taken very positively when the Apple app store launched. It was much lower than what software companies typically budgeted at that time for marketing and distributing a new product.
Of course it didn’t take long before the App Store was so full that anyone who wanted scale had to do additional paid marketing anyway.
