[mendicant]

I will start by saying that the sentiment of this is simple and true. The value added by the "Unlock All" button in it's simplicity is valid.

But they didn't "just add a button" they also added over 3x the content to give that button value.

If they had kept their original 3 books and added the button I'm guessing they would have seen next to no difference in the bottom line.

My point being that in order for an Unlock/Buy All button to work, you need to have enough content/product/etc to make the button worthwhile. Just adding a button may not be enough.