Microsoft has been making hostile moves on licensing for on-prem/non subscription products for a while now. They want you to give up on local resources. Of course you could go to a competitor, but the only large competitor in the US is basically Google, and their offerings are not well tailored to business.

Basically, my company is tightly wed to using outlook and exchange.

We would have liked to have kept all this "on-prem". Meaning, we have physical machines running in our company network that has paid licenses for exchange.

The "force" that Microsoft has applied, is that we will not be allowed to purchase licenses for exchange (disclaimer: I don't know if the licenses are not available/discontinued or if it's not cost effective - I wasn't involved in those conversations). Long story short: If we want Outlook/Exchange we must use MS Cloud solution. Depending on your organization's size - this cost us an ungodly amount of money but (and here is where the anti-trust is) you get Office 356, Teams, and the rest of the MS eccosystem "for free" (or at a deep, deep discount).

This means the cost of Cloud Exchange (which includes Teams, O365, etc) . Was about the same (maybe a little less) than what we paid for "on-prem" exchange, plus Google docs, plus slack, plus Zoom. However, since "on-prem" exchange isn't available - our only other option would be to ditch exchange for Google (which costs a lot more) or some open-source solution (which probably won't integrate seamlessly into outlook).