Nothing other than a full blown exchange alternative.

I think the thought that SM will become a full blown exchange alternative is a bit of a stretch at this point... Very david vs goliath at this point. 

In all honesty, i see the market place being the best alternative to exchange right now. SM should separate out any "non-core" features into modules, and then let the community / 3rd party developers build these modules. If SM just focused on CORE code, instead of trying to integrate new features all the time, we'd probably have less issues. And with exchange being very closed sourced, being able to integration hundreds if not thousands of other tools would give SM an amazing edge (if they can implement it right...)

Plus we all know at some point Microsoft is going to run afoul of anti-trust regulators that will demand steep changes to the platform to be competitive.

For us, it's not just about an exchange alternative anymore. It's about a Microsoft 365 with Teams, Google Workspace with Meet, Zoom Workplace, Icewarp, etc. alternative - a complete communication, collaboration, and whatever-tion hub with email being an integral part.