Even companies that were all-in on Google for email, calendar, and documents went with (for example) Slack for chat and Zoom for meetings. Google has had multiple products in both categories for years! And yet somehow could not put together a compelling package the way Microsoft did with O365 + Teams seemingly overnight.
Microsoft still hasn’t shut down Lynx yet.
The companies I worked at that had slack licenses still had teams using what they considered to be the best product. Slack, Hipchat (remember them?), and Zoom.
There's also more to it than 'bundling.' Trusting your chat communications to the same company doing your email is a more compelling story than sending it to Slack, Discord, or Zoom. There are a lot of companies that still don't trust 'the cloud' and then you've got governments all over the world and all of their regulations that may block the use of something else.
Their monopoly lawsuit behavior was different — the bundling of windows with forced IE was problematic (largely because windows was everything, and also IE being largely unrelated to the rest of the OS) but much more problematic was their OEM strategies, to enforce and maintain windows as the dominant OS.
Ask Slack if they agree. Microsoft used the dominance of Office to take over that market by bundling Teams.