How do they intend on competing in the enterprise space? MSFT and Atlassian will happily bundle their SCM offering for 0 dollars if you spend enough on licensing other core products like visual studio or jira.
One migrated from Github Enterprise Server explicitly as a cost saving measure. One migrated from Bitbucket Server because the writing seemed very much on the wall for Atlassian's self-hosted solution with the Jira pricing model change and a trial migration from Jira Server to Jira Cloud had gone so badly the whole thing was called off (though they did pay up for JIRA Data Center, JIRA was deemed less replaceable than Bitbucket apparently). The last went from Gitlab CE to Gitlab EE, so maybe there wasn't the hardest investigation of alternatives on that one, but they did at least claim they looked at Github Enterprise server as an alternative.
Now none of these companies used Exchange, Azure, Office, Teams, etc. etc. so maybe there's a bunch more discounts and synergy if you're fully bought into the MS ecosystem