I must be old; if Microsoft had even suggested taking a 30% cut of every PC application or purchase via the internet they'd have been lynched. Have most developers gone conformist/apologist?
It isn't all that different than what you see elsewhere in the economy. Now that there are just a few large corporations who effectively control the food supply, they increasingly get a larger share of the profits at the expense of the many supplying farms.
If there were 10 different Apple App Stores you could sell your applications through that were all of equal quality, then the cut Apple requires would drop off significantly.