I doubt the employees will make a difference. It is likely more about the lobbying power of Microsoft and them finding a person at the right level who is recept

I doubt the employees will make a difference. It is likely more about the lobbying power of Microsoft and them finding a person at the right level who is receptive to their appeals and has the power to revert the policy. There are a lot of tech people who appreciate open source software and understand the benefits of digital sovereignty but its rare for them to have the final say in most orgs. Just about every org in my country uses Microsoft's email including universities, government, schools, businesses. I am sure it has some features that make it a good choice but its is unusual for any product to have practically 100% market share and no competition regardless of technical or usability advantages. Microsoft has huge resources and knows how to win customers.