So VRML's a 3D file format, and A-Frame's an entity-component JavaScript framework. Check out https://github.com/aframevr/aframe and you should be able to discern.
VRML both had node definitions and a scripting part, it's not just a 3D file format in the sense that it's not just describing 3d meshes but also how to interact with it.
True, but the interaction pieces were still part of the format, and probably limited in power. Though I'm a bit too young to have been experienced that era, so I don't fully understand the comparisons.
But I know today A-Frame has full access to JavaScript, DOM APIs, three.js, and Web so it's looking more towards building full stateful applications.
Yes. Personally, I think VRML's biggest flaw was that it was ahead of its time.