I think they still had an advantage, as Blackberries had push email even on the standard BIS (not BES) service. I remember early Androids and iPhones needing to poll the email server occasionally to notify you about new emails. Switching poll frequency to every 60 seconds killed the battery, but it was the closest thing to BB's push implementation.
iOS had support for ActiveSync in 2008. A year after the iPhone was introduced.
Ah, I see. So corporate users who likely get email from an Exchange server would have had pretty much the same real-time email access as most Blackberry subscribers.
Yep. In fact, I get an email notification from my phone/watch a second or two before I get one from my computer running Outlook. That has been basically the case since day one.