This happens because of how Microsoft approaches product development and design. On many product teams, PMs end up doing not only the product design decisions but even designs much of the products themselves.

This works for them because it focuses product cycles on releasing what "matters" to the customer, but it ends up cutting craft and quality. This makes their products poor to use, but is also what drives revenue into their hands.

They don't really need to be the best or the fastest. They just have to have decent products that aren't the worst (I prefer Teams over Webex), and glom those products together into an affordable package.

For better or worse, Microsoft product suites are like the Olive Garden of the product world.

edit: whoa, got more comments than I thought. For disclosure, I did a brief stint as a PM intern there way back in the day. Wanted to join as a UX designer intern, but got shoe-horned into the PM role