This is the spiritual successor of that. "Webmaker" changed from a single product to "a suite of products" at the time, with this tool getting renamed to "Thimble". That thimble used Code Mirror for its editor, and only allowed you to write a single file. Since webpages aren't single files anymore, and haven't been for a while, we made a choice to try to integrate quite a few technologies (Adobe's Brackets as editor with tons of features, Filer for faking a POSIX filesystem in the browser, etc) into something that is both the same, but also a lot better, and the old Thimble got turned off (after about a year of having both up at the same time) last June.
We didn't, mostly because VS Code didn't exist yet when we added in Brackets. It got released when we were already beta testing, and was still in extreme beta by the time we officially launched the updated tool in August 2015. It would be interesting to see how many other now-existing solutions might work for the code editor part, but at this point it would disturb quite a few people who now use Thimble in the classroom or at learn-to-code events, so while as a contributor PR it would be fantastic, we don't have the man hours to investigate a completely new code editor component (with its own UI that needs tailoring, filesystem requirements, plugin infrastructure, etc).
