It also has the benefit of inertia. Everyone knows Microsoft from either school or marketing. They are the standard and anyone else has to fight decades of standards. It also helps that they historically created the best tools for easily managing fleets on machines. Now days they are pushing everyone to Azure but before they had the best tools to build your business on. It was so convenient to have Windows server with all the server stuff like AD, SQL and IIS. They basically were they only well known option until the last 5-10 years.
It also has the benefit of inertia. Everyone knows Microsoft from either school or marketing. They are the standard and anyone else has to fight decades of standards. It also helps that they historically created the best tools for easily managing fleets on machines. Now days they are pushing everyone to Azure but before they had the best tools to build your business on. It was so convenient to have Windows server with all the server stuff like AD, SQL and IIS. They basically were they only well known option until the last 5-10 years.