This month's rollout of sub-issues and issue types would be most of what my organization thinks it needs to shift to GH Issues, I believe, barring however long it would take to rewrite some sync up automation with ServiceNow based on those issue types. Of course it will take another 6 months to a year before those kinds of features make it to GitHub Enterprise, so it is still not happening any time soon. (Though that gets back to my "weird" mixes. I don't entirely know why my company is using AzDO SaaS for Issue Tracking but decided GHE over "normal" cloud GH for Repos. But that's not the weirdest mix I've seen.)
I definitely get the backwards compatibility thing and "don't break someone's automation", but at the same time, Microsoft could at least mark AzDO's official Roadmap as "Maintenance Only" and send the message that feels obvious as a user that GitHub is getting far more attention than AzDO can, but is hard to convince management and infosec that a move to GitHub is not just "the future" but "the present" (and also maybe "the past", now, given AzDO seems to have been frozen ~2020).
I definitely get the backwards compatibility thing and "don't break someone's automation", but at the same time, Microsoft could at least mark AzDO's official Roadmap as "Maintenance Only" and send the message that feels obvious as a user that GitHub is getting far more attention than AzDO can, but is hard to convince management and infosec that a move to GitHub is not just "the future" but "the present" (and also maybe "the past", now, given AzDO seems to have been frozen ~2020).