I thought the entitlement was google's when they used open source development to build their closed tools and betatest their api/protocol.

Of course the entitlement is theres because they convinced OSS devs to write code for them for free under the "do no evil" moniker.

So now if they want to keep their toolchains, they have to continue maintaining the oss-side google service apps to regain access to the tools they help built.

I think this is called bait and switch, and it's probably the #1 pattern used by big technology firms today. It's so easy to "switch" with IT. Carrot-stick pattern worked well for Microsoft, because they owned the only stick and most the bait, but no longer. I guess without a monopoly, the only way to secure customers is to fool them.