They did handle the growth from search to email to integrated suite fantastically. And the lack of a broadly adopted ecoystem to integrate into seems to be the major stopping point for emergent challengers, e.g. Zoom.
Maybe the new paradigm is that you have your flashy product, and it goes without saying that it's stapled on to a tightly integrated suite of email, calendar, drive, chat etc. It may be more plausible for OpenAI to do its version of that than to integrate into other ecosystems on terms set by their counterparts.