It isn't so much about Altium features being that gating element. Given what was coming in KiCAD 6.0 I made the decision to make the transition with that version. Altium has turned into a complete mess. Bugs keep piling up. They release hot fixes and create new bugs. The company seems to have focused on attempting to migrate the user base to a cloud-based subscription model and, in my opinion, made a complete mess. They may have been targeting acquisition by Autodesk too, which never happened.

At $2000 per year per license, it is very hard to justify Altium Designer except for the very low percentage of boards that might require specialized features. KiCAD is good for probably somewhere in the range of 90% to 95% of the boards anyone makes. Let's put it this way: I've created multilayer gigahertz-range controlled-impedance boards with far worse tools than KiCAD...not sure what the $2K per year/per license gets me in the case of Altium Designer any more.

And the best part of this is that KiCAD will get better and better over time. We plan on contributing both financially and with development of either plugins and more. We all win.

I see this as the GIMP vs. Photoshop case. At some moment in time GIMP became good enough. After that it became better and better. For most users I think I can say that they would not feel like GIMP lacks anything important these days when compared to Photoshop. KiCAD is definitely headed in that direction.