People and organizations that built things on top of Microsoft tech. Especially with a long history going back to NT times.

HN, YC, startup environment or academia is a Unix bubble. They all feed into each other. Especially because Linux is gratis which helped all of those to deploy projects/products/papers cheaply. Unix systems traditionally lack much of the upper layers, so it is the responsibility of the company, persons, developers to deal with the OS minutea. You need sysadmins, devops, SREs. Those are common roles again in this Unix bubble. The dependency chains here are usually flatter since it keeps mid-term costs lower.

Other organizations like governments and bigger orgs like banks prioritize having somebody else liable (i.e. they can blame) and they prefer to not hire technical competence in their orgs but rely on other companies. This is where Microsoft gets a lot of clients. You buy a bunch of server licenses. Your Microsoft support person installs them and installs IIS via GUI. And then you just upload your code every now and then. The OS updates, IIS server etc are all the responsibility of Microsoft and the middlemen companies. Minimal competence from the orginal org is required. There are multiple middlemen businesses who all give zero fucks about anything but whatever the immediate downstream from them. This is more usual in already publicly traded huge businesses. Moreover the investors actually mandate certain things that only this kind of layers of irresponsibility can deliver :) So you see this kind of switch happening towards IPOs.

Azure is the cloud labeling and forcing the first paradigm over the second paradigm for Microsoft products. It got lots of support because shareholders liked it. I don't think the original NT design and Microsoft's business model was bad, it actually worked very well. However, shareholders gonna shareholder. So they pushed hard for Microsoft and their clients to move to the "cloud". Microsoft executives saw the huge profit and share value potential of pushing Azure the brand too. It was the AI of 2010s afterall.