They have a pretty good migration schedule
Yeah - for your PERSONAL stuff that takes you 20 minutes to migrate or backup.
You've clearly never managed an enterprise software product. The entire point of enterprise software is that it affords deep integration into your workflows and internal processes and systems throughout the company.
I'd be more impressed with a number of products if they permitted you to continue running them on their cloud services, after they have ben generally end of lifed. I doubt that anyone would be continuing to run Google Reader or similar products which were nothing but money-losing propositions, but there are other products that have been EOL'ed that I could imagine an enterprise wanting to keep something around for an extra 6-8 months to actually get their business processes migrated some place else.
If you're going to kill something like this, something on which a business has become dependent for day to day operations, and you are in the business of selling cloud services, you might as well open source the thing, since it's already tied to your back end cloud services anyway, and the worst thing that's going to happen, since those services are based on a proprietary platform, is the company gives you more money. Absolutely worst case, you don't open source it, but you time limit the contract so no one takes your sources and ports them over to OpenStack.
they have quite a few other products that either manage to substantially offset their costs or give profits.
No, they really don't. 95+% of their revenues are generated by advertising. They make virtually NO money from any source that is not advertising. Go look at their financial statements.
I think this is something that's frequently lost on people, Google has one main product, and they have a couple of vehicles that they use to deliver that product: primarily search, and secondarily AdWords/AdSense, with gmail at a distant third place. It's not even possible to argue Android, since nearly all productization of Android is done by code freezing the source tree, and the partners, not Google, productizing it to bring it to market. This might change with the purchase of Motorola Mobility, but I wouldn't count on it.