By the time announcements like this are made, there have already been lengthy successful IT pilots with much change management planning already conducted, partn

By the time announcements like this are made, there have already been lengthy successful IT pilots with much change management planning already conducted, partners engaged, etc. If they say 12-18mo, they may slip to 18-24mo, but definitely not multiple years. That said, the other commenter is also accurate: a "full" roll-out will not mean 100% replacement. Things would break and it would be an irresponsible management decision to force some things that shouldn't be forced. Source: I led a large MSO-->G Suite migration in a previous role.