We get calls and emails from clients all the time who have deleted their Google Analytics account and are looking to restore it. We sadly had to send them elsewhere, as there was really no way to restore any of that data once deleted.
In the upcoming weeks, GA will finally be instituting a trash can. You have 35 days to restore what you’ve deleted. While the trash can won’t be available immediately, starting today what you delete will appear there when it is rolled out.
As for past data before today? Not sure if that is recoverable, might have to let it go.