Earlier quoted context omitted.
When you signed your agreement, that Android technology didn't exist, so reserving themselves the right to get root on your devices accessing corporate information was the closest, yet very blunt, approximation. Personal devices were highly discouraged or even forbidden for a long time, but employees kept asking about them, for the convenience. These use cases and internal dogfooding were major factors in the eventua…
That doesn't track. By the time they pulled this crap (including the "you didn't sign it, would you sign it again?" and it turned out to be different), we had been given at least one Android phone (ADP1) and maybe the second as well (N1).
I definitely had my personal account as the primary on my N5 along with a work profile and I believe that's the first device/OS combo where it was feasible, if you ignored the annoying duplicate app icons in the launcher. The first truly "tolerated" personal devices were probably the Christmas gift Chromebooks from a few years earlier, as long as you used Yubikeys.
Didn't the policies even predate Android? They definitely were there well before Lollipop. Unless they were introduced post-Aurora, in 2010 — i.e. in the N1/Eclair days, keeping the phone vintage theme.