My take is that in the most central sense, what Nadella and Microsoft are doing with the code editor, .NET, their free IDE, etc. is following a standard, powerful, old script:

If have something popular, e.g., .NET, then make it open and promote it as a standard. Then come out with enhancements every few months.

Part of the script is what Ballmer once said in his uniquely understated way -- "Developers! Developers! Developers!"

Then initially many developers will adopt and use the standard because it's open and, thus, close to universal, at least pretty good, and free.

Then, later, as Microsoft makes improvements each few months, it will be next to impossible for anyone else to make a fork that is competitive so that Microsoft will, then, continue to own the standard. Or, if a developer wants some new feature X, then they will likely just wait for the next version of the standard and hope.

So, thusly owning the standard, Microsoft controls a major part of computing which can be very powerful for Microsoft and a farm where only Microsoft plows, seeds, and harvests.

E.g., nearly all the developers would be on .NET, etc., but Microsoft and only Microsoft knows where the .NET standard will be in version n + 1, n + 2, ... out several years into the future. Then the rest of Microsoft can start development now that exploits the standard, say, two years from now while everyone else has to wait two years even to start. Bingo. Presto. The parts of Microsoft that exploit the standard get a two year head start.

Or, maybe at one time a computer company, say, HAL, designed, manufactured, and sold hardware, operating system software, middle ware software, and applications software. Then they had hardware enhancements right along, say, each year or so.

Well, the hardware specification about had to be in the manual Principles of Operation and, thus, essentially open. So, some plug compatible manufacturer, say, GA, could get the manual and build a cheaper version of the hardware.

Well, the HAL software people knew what good, new functionality was coming to their hardware some years before GA or anyone else did and could have a head start of those years. One heck of an advantage.

Net, thusly owning an open standard can be very valuable.