@david_chisnall I do wonder how the output of such a tool should look like these days, though. That was one of the major issues of a lot of the prior art, sometimes intentional (HyperCard), sometimes more by accident (Tcl/Tk).
Regular "HIG" GUIs had the advantage that you could follow a lot of patterns, so you just needed to overcome not being a "proper" programmer, not also not being a designer.
These days, those kind of UIs are basically retrocomputing, and you either get some flashy web page or something on the desktop that is increasingly Blender-ized.
Hard to find a niche for end-user programmers there, even if the purely technical issues are resolved.