Yes, ASP.NET Webforms is outdated, but it's still around, and I think many developers are looking at moving to a newer and more modern technology. But in some cases - including mine - it's not really possible to refactor an application that has grown for 20 years overnight. The only thing I can do is put a lot of energy into changing the CSS of the controls. Which is not always easy.
I really appreciate the functionality of the Telerik controls and think it's a shame that they don't get a visual and functional update.
In this specific case, it is about the Datepicker Control, which has a different behavior than the more modern version under .NET Core. For example, the month or year selection opens in a new DIV popup. In the more modern control, this is solved in a more elegant and modern way.
I think that this list of controls that need a “front-end pimp” can certainly be extended.
Thank you!