Possible, but from the inside as a Microsoft Partner, it feels like most of the world is just starting to move to the cloud, and when they do, they go Azure, because they are already dependent on Exchange.
But one thing people often forget is that AWS is cheaper than everyone else. This matters to most companies.
Also, Azure is a pretty miserable dev experience for many of their services. Many of AWS smaller services aren't great, but better from what I've used/general sentiment.
Can you provide a source for this please? I recently priced out AWS, Azure, and GCP for GPU workloads. I found that AWS and Azure were approximately on par, whereas GCP was significantly cheaper:
AWS p3.8xlarge: $12.24/hr [1]
Azure NC24 v3: $12.24/hr [2]
GCP n1-highmem-32: $8.311/hour [3]
[1] https://aws.amazon.com/ec2/instance-types/p3/
[2] https://azure.microsoft.com/en-us/pricing/details/virtual-ma...
GCP is, AFAIK, usually cheaper; but AWS is more established, and the “no one ever got fired for being buying...” player of public cloud (which has to chafe MSFT, since they pretty much displaced IBM in that role for on-prem.)
Alternatives for Exchange usually go in the direction of outsourcing (which ironically can mean: still Exchange, but not in the ball-and-chain on-prem way). Cloud options exist, but for people who for whatever reason require something to physically exist at a specific location (which is weird for email) commercial offerings are plenty (i.e. Zimbra, Zarafa, IBM's stuff, Red Hat's stuff, Oracle's Stuff).