Any organisation of this size with so many different products will have these kind of problems. This is not really a "Google problem".
That's probably a good reason to avoid organisations of these sizes unless you have a good reason not to, but ... that applies to any organisation of comparable size.
I agree to some extent only. Any big organization faces this issue, so you're right this is not just Google problem.
However, they way they approach it varies considerably, and I'd expect Google engineers to address it in a way that minimizes problems resulting from, say, changes in product A causing problems in product B. I'd bet some work on that has already been done because these folks aren't stupid but apparently that's not enough.
That's probably a good reason to avoid organisations of these sizes unless you have a good reason not to, but ... that applies to any organisation of comparable size.