I'd much prefer a reality where the play service and app is open, and which upstream source you trust is defined by which certificates you trust, and nothing else. That'd make it trivial to set up trusted sources for a company, for example.
So, I would like to run Free software on my devices. Thankfully the kernel is still Free software, so there's still hope we can have open distributions going forward. It seems a shame to double the work to achieve that goal, so I think it makes sense for the software to be opened up.
You didn't answer the question--what makes you believe you are entitled to free software from a company that employs thousands of people to write it?
However, the pony in this analogy is the device, not the software. The software is more like the saddle -- and Google are selling ponies with their own custom designed saddle, making it hard to ride it any other way than bareback if you don't use Google's saddle - so that they can sell adwords printed on the saddle, and take a cut from everyone that sells Google compatible stirrups.
At any rate, I didn't say I was entitled to it, just that I couldn't see any reason to keep it closed. I do see many reasons to keep it open.
There's certainly a lot of work put into making the stuff work -- but opening up the code won't make it stop working for Google. And I really doubt there's much fancy in there - mostly just grunt work to implement some straightforward ideas. I fail to see how opening that up under something like the GPL or AGPL, preventing someone to (legally) take the code and "run away" with it -- will lower the value of the Android system.
Now that Google has to worry about de-Google'd Android products, they need to keep more of their work for themselves.
That's the antithesis of open.