And yet some would argue that Google has begun to get search wrong. What happens when the "right" identity solution does the same?

You get another one. There's no true stability in this world. You try your best to find an optimal solution and keep working at it.

you could argue, but statistics would show you otherwise for the foreseeable future. regardless of wether or not they are 'losing it' they clearly got it right for a very long time.