So much on this topic lacks real grounding.
1. Apple's take is legal. Even Sweeney admits his objection is only on bad faith grounds; there's no failure to comply.
2. Gruber and others want Apple to be nicer. But doing more than the law requires just invites more lawsuits.
3. People objecting to 30% fail to mention the small-business program, where if you have revenues below $1M, Apple's take is 15%. So these businesses are significant, and many, many years of expectations are baked into their business models. Discounts for nothing would just be a giveaway.
Regular people are entitled to have their devices from Apple just work: no viruses, no adversarial software, no snooping by Apple or others, no creeping data overages, effective and automated (security) updates, and no premature end-of-life. The cost of even a little bit of that would be the biggest tax on productivity and enjoyment.