User-474980206 posted
.net framework 4.6.1 is not the paid version, its free. there are also paid and free version of visual studio. you are paying your msdn subscription for developer tools, not sdks (which are free).
.net core is the replacement for .net framework. core is getting the new features, not .net 4. .
as currently desktop and store apps can only be written in .net 4.*, new store and o/s feature support is added to .net 4.*.
this year, .net core 3.0 will support desktop and store apps, so this will probably slow down adding features to .net 4.*
asp.net core is where the asp.net development team is spending their time. they are only adding features to asp.net core (rtag helpers, razor pages, razor components, blazer, etc).
if you need windows features or have a lot of legacy code, you may want to wait this asp.net core 3.0 is released this year. but if this is not an issue, then you probably should switch now. at min, you should start learning the changes that come with core.
note: asp.net core does not support vb.net (libraries written in vb.net are supported, so the BI and DAL layers can be vb.net), so vb.net users should stay with asp.net 4.*