At least in case of mailbox, I would say they were sherlocked by Google Inbox: nearly as good an UI but without the need to share access to email with a third party.

I really never liked that aspect of mailbox and I thus never used it with my primary mailbox, which meant that I practically haven't used it at all.

The moment Inbox came out for google apps, I started using it to the point where it is now my primary means for accessing my mail.