You are absolutely right, and I work with users who would fire someone in the dev team if their WPF app ever went down during the week (the app is kept running for 5 days of the week). This is necessary for many trading platforms
UWP is unfortunately not a modern version of WPF. It is an adapted form of the Windows 8 'WinRT' platform. It originates from Silverlight of all things.
This is part of the problem, its almost impossible to create WPF-like 'power user' experiences with UWP - as its design philosophy is 'mobile first' and 'touch first'.
Enterprises who would think of building apps with functionality that can be delivered with a UWP app are more likely to just build a web app - its cheaper and requires less maintenance.