Some of these breaches, for instance the Gmail/Google breach, might have not been a breach of there systems at all. So far for that example (but there are more)

Some of these breaches, for instance the Gmail/Google breach, might have not been a breach of there systems at all. So far for that example (but there are more), one could apply that to Outlook/MS and get identical results. Aka; hack some service that has millions of emails/password (accumulated), filter all gmail emails, try to login to gmail with that compbi and if it works, put them into the list of 'hacked gmail accounts'. Not trying to stick up for Google here, but, like MS, there seems to not be a real breach there.