I don't really see the cancellation having much more than a negligible impact on the marketing only. I certainly don't see it affecting an announcement or release schedule. If the assumption is correct that the next Civ game reveal is imminent, surely the announcement, marketing, and release schedule have all been fairly nailed down already.
For context, by the time of E3 in 2016 we'd already had an announcement with trailer, three first looks, and a community Q&A stream in the intervening month and a half. All E3 did for the broader community outside the event was to provide a couple walkthroughs of the game. Something that could just as easily be done w/o a connection to a particular event. Though SGF would be a viable alternative.
For context, by the time of E3 in 2016 we'd already had an announcement with trailer, three first looks, and a community Q&A stream in the intervening month and a half. All E3 did for the broader community outside the event was to provide a couple walkthroughs of the game. Something that could just as easily be done w/o a connection to a particular event. Though SGF would be a viable alternative.