In many ways this open source tooling is making them money. Developers tend to use what they know and are comfortable with, if you have to move off of C# say in

In many ways this open source tooling is making them money. Developers tend to use what they know and are comfortable with, if you have to move off of C# say in order to write servers with better Linux compatibility or mobile apps you're going to learn something else and may not stay in their ecosystem. If instead you use .NET Core for your Linux based services and buy Xamarin for your mobile apps, they're in a lot better condition, especially given that they can offer to host those Linux based services for you on Azure as well as dozens of open source databases and tools which may support them. They're making a killing off this, many companies have gone to pure Azure services given that they're able to host everything they need there, had they not been able to that money may have gone to Amazon or Google, investing in open source is generally a good move for them financially. They're now less and less reliant upon everyone using their exact stuff - as long as your corporation still wants a Windows domain controller and MS Office, they're on top of the list for cloud considerations and will easily make money hosting open source software - they lock companies in in other ways than software, like Office 365 and Active Directory login integration with your Azure hosted applications. There's big money in hosting and managing open source software, Amazon and Google discovered this before Microsoft, but Microsoft has been quite competitive given these advantages.