Also, .NET 5 is now here, and 6 is already in preview, which are much, much more backwards compatible than .NET Core 3. And unlike Python, we had .NET Standard to start migrating code between Framework and Core. A lot of extant code on NuGet has already migrated and there is really very little you can't do these days.
Unless one is using third party controls, CMS like SiteCore, SharePoint and Dynamics, writing custom .NET code to be called by SQL Server stored procedures, having a working WCF infrastructure, using RDMS with EF 6 that isn't SQL Server, in-house stuff that isn't fully covered by the Windows Compatibility Pack, and a couple of other little things.
Also asp.net webforms is not supported, webservice/soap are 'supported' but the tooling is broken and i don't think you could extend a system with it in modern VS. The winforms editor works but is buggier with each new version, and asp.net mvc projects are similar but changed, and I'm sure the list of issues continues.
Also from my experience coaching and consulting there's a significant learning curve for .NET framework developers to work in the new core/.NET 5 systems.
So keep using .NET Framework. v4.8 is only 3 years old and there is no end date set on the support yet. Considering the last version of the v3 era will be supported until 2029, I'm sure the last version of the v4 era will get quite a long period of support as well.
I bit the bullet and transitioned from WebForms to ASP.NET Core. I think it's easier than WebForms ever was. You can replicate 90% of what WebForms did with Razor Pages, but you also get much easier support for building RESTful APIs. And with DI built-in, I don't have to worry about junior devs forgetting to close/dispose database connections ever again.
On my world those decisions come with project budget, if no department puts the money to hire the consultants that would do the job, there is no transition.
What do you want me to say? Because your organization is stuck in the past, that means .NET can't move forward?
If you've followed the .NET blogs at all, they have very good reasons they haven't prioritized support for these legacy systems. There isn't some cabal of platform designers in Redmond scheming on how to screw over developers at ossified orgs.
Not sure why I'm bothering. Everytime someone mentions .NET on here, someone comes out of the woodwork to complain about their pet features not being supported. Actually, come to think of it, it's often you in particular. We're going from .NET Framework being fundamentally tied to Windows to a new .NET that runs on everything. ASP.NET was built on HTTP.sys, a Windows driver for a web server. I don't know, is it terribly surprising that trying to migrate .NET off of Windows-only dependencies is going to break things downstream?
But if you still need this stuff that only runs on Windows, well, you got at least decade of support to look forward to.
It is not me that is asking, rather the Fortune 500 companies where software development is a cost center, that hire us to keep their production systems and factory lines rolling.
