Despite the old FOSS adage the "software wants to be free", it isn't really the same as with humans or animals. So, that's simply a non-sequitur. Next!
It is not a non sequitur because it is self evident from the people who jail break their phones, install firmware and all the rest.
Apple's distribution model allows for distribution to up to 100 devices, and Apple has programs to allow bigger organizations to distribute in-house apps to more devices than that, without involving the App Store or it's Approval Process. Next!
Ooh 100 devices. Wow that's a huge enterprise! And even if it were IOW, that .0000005% of apps I was talking about...
No. Amazon's store is very popular as are many other app stores / downloaders. e.g. Humble Bundle sells games for android and distributes them through its own software.
I'm not sure what you mean by Vertical Applications; there are a ZILLION Vertical Apps in the App Store.
Maybe you look up what a vertical application is then. They are very specialised applications, may cost a lot of money to make, may cost a lot of money to buy, might have specialised revenue streams which don't work within the rules of the app store and the vendor (and customers) might strongly resent Apple / Google stealing a 30% cut of everything.
As far as Open Source Apps, I don't think Apple has any restrictions on you offering the Source to your App through another website. They are only interested in assuring that the Apps in the App Store are SAFE. Next!
Don't be ridiculous. Lots of open source apps are prevented from listing on Apple's stores. Anything related to shells, scripting, su, compilation, proxies / filters, emulation, file transfer stands little chance. Even Google has some limitations and would probably respond to takedown notices whether fair or no. But that isn't a worry since there are stores such as F-droid where open source apps are available from.
Frankly your excuses are pathetic. The reality is that being able to install APKs from external sources is a strong benefit of android and many people legitimately use it. Freedom doesn't mean common sense, but it not should be taken away because some people lack common sense.