SmartThings is in the middle of a huge transition from one architecture to another. The Samsung hosted free groovy cloud will be going away, which means anything that uses that will no longer work. And that includes all the custom smartapps like Webcore. 
The replacements for device type handlers will be “edge drivers“ written in Lua that run locally on your own hub.
And the replacements for smartapps, including Webcore, will be routines in the smartthings app (which have a lot more features than they used to), And the “rules API” which is a whole forum category in itself.
But with the exception of the new features in the routines in the app, everything else is still in beta and still undergoing changes.
So, yes, very few people are creating new stuff in Webcore for smartthings now. But you should be able to do the same thing another way that works with the new architecture, I just don’t know the details of that.