I don't know about Blender, but for QGIS I think open or at least well known formats are what gave it a chance to compete against ArcGIS.

For CAD, I think that an strong open format would make things much more easy for FOSS CAD software. I can see this starting happening with BIM.

I believe in freecad! It's not there yet, but the latest release is a lot of progress!

When I finally Get Around To™ learning CAD, I'll definitely invest my time in FreeCAD.

Hmmmm... even though I'm a cheerleader for it, I wouldn't recommend starting with FreeCAD. Learn on something more feature-complete and with a less idiosyncratic UI, like Onshape. I learned Solidworks at work and without that foundation I wouldn't understand what's wrong / missing about FreeCAD (which is still a lot).