I have been working in an corporate environment for the last 8 years. Initially we were using G-Suite. It was cheap and got the work done. Then some day, IT decided to switch to office 365 and SharePoint. With that came a number of apps like Delve, Dynamics 365, Flow, Kaizala, MyAnalytics, PowerApps, Stream, Sway and many more. Recently, our laptops were upgraded to Windows Enterprise. It has been more than a year now and still no one uses any of these apps! We have full fledged SAP in use today.
That might be true, but for an office network it's not actually about what everyone uses. It's about having the capability to serve everyone, including niche users. If there's even a small portion of people on your network using those apps, or one drive, azure, accessing shared drives with permission versus web etc, they might be considered useful.
Occasionally an office will set up a single local computer for something rare, but it's often easier to build the network with groups in mind - accounts, retail, support, tech etc, and make sure each of those groups is being fully served. That's usually easier to do by building in more than what 'most people use'.
That said, windows as an environment for running niche industry software, and office are absolutely core, but so is MSFTs cloud services.
When it comes to 'services' however, it's not like anyone, not even google is making substantial earnings compared to core business for say onedrive access, or putting office on phones. The entire main of that, is to 'draw people into the ecosystem', rather than earnings per se. Which is why MSFT bundles a lot of it's stuff.
There's no large amount of earnings in app subscriptions on mobile. Even apps are outstripped on android - 100 million use the outlook app, 400 million use outlook.com, and only a tiny proportion of app users will be getting premium. The core mobile office apps are free, and you get free access beyond that from an office subscription - something people are rarely going to get simply for android access on larger devices.
Same story with skype. This argument that somehow android is going to bring in the beans, simply because microsoft sells software, ignores that android is a low margin software environment. It's all cheap. Only massive volume add up to anything. And microsoft is already bundling almost everything, so it's only really added value if you have a PC.