Re: "Freezing out third-party apps"
Oh dear Wade, here we go again for the hard-of-thinking...
This is not about the ability to side-load from outside of the Google app-store, this is about the bundling of key Google data-slurping processes and the dependency on those in many apps. The reasons Google is abusing its position compared to Apple are:
1) Apple make and sell phones. No other company uses iOS or Apple's store. Thus Apple can't pressure, say, Samsung or LG, or Motorola, etc, to bundle something in Apple's favour.
2) Current market share (http://www.idc.com/prodserv/smartphone-os-market-share.jsp) shows that Android had (2015) 82.8% of the market compared to 13.9% for Apple's iOS. Once you are well over 50% you get enormous leverage in terms of compatibility, developer attention, etc.
This, and in particular the forced installation of Chrome, is exactly the same as MS' abuse of its OEM licensing in the past. However, I doubt the US regulators will act, or if they do it will be shut down by a change of gov who happens to be "pro-business" (in other words, enjoying the lobbying funds).