That's the point, they don't need market optimization to continue improving their product. They are just leveraging it because it's a weapon provided to them. There is no lack of adequate competition in the chat space and no need for the government to make MS stop including the products it wants to in its office suite.

While this individual action may appear on the surface a net gain for everybody (though you surely meant everybody but Microsoft), the net negatives of continued unnecessary government interference in tech are harder to recognize since each just increases legislative momentum. Then we get surprised we weren't stauncher and more principled when the heavier hand is shown.