"Subject to the deprecation policy [which says that Google will give at least 1 year notice before cancelling services], Google may discontinue..."
In other words, at any time, google can give you a years notice.
(I work at Google, but am not a lawyer and this isn't official in any capacity).
Please don't selectively quote things out of context to give a misleading impression.
> commercially reasonable
> substantial economic or material technical burden
Is one engineer working on an old service to keep it alive commercially reasonable or a substantial burden? I don't know. Do you?
In practice this policy lets them shut off anything they want any time they want. Again it's their playground they can do what they want unless they signed a contract saying they'd do something else for you so I don't have a problem with it.
To be clear, that policy is a contract. And those things would be decided by a jury. And if my understanding is correct, the reasonable person standard applies. So you can answer this yourself, do you think a reasonable person would believe that your interpretation is valid?
If not, why mention it?
Because it makes more people feel comfortable enough to use your services and pay you, without actually binding you towards any sort of behavior that would cost you money. There's a direct financial incentive here to use legalese to give the semblance of reliability without having to deliver on it