Yes, device management systems can push apps directly to devices, but the devices have to be managed first. So I think it probably is about the lack of Google Play.

One of the hardest parts of managing devices is getting them enrolled in device management in the first place. Microsoft uses the Microsoft Authenticator app to authenticate users as part of the enrollment process, so they know which employee is using the device and how to configure it. They need a reliable app store to distribute that app, and they need to do it before the device is managed. So usually they rely on Google Play.

And IntelliSync, so you could have the same contacts in your PC and your Palm Pilot.