Live synchronization of layout and schematic files is a feature you find in EAGLE, but in almost no other EDA program.
If you say KiCAD is not an professional EDA due to missing live synchronization, the same argument applies also to Altium, Cadence Allegro, and most other EDA systems which are considered as professional by most people.
Fine. KiCAD's manual tool still gives me more trouble than Altium ever has. How about the lack of a built in autorouter? Infuriating wire placement UX? We can keep going here.
Those numbers are likely biased toward hobby electronic designers located in Europe and USA. It would be interesting to see the numbers from manufactures with different target audiences.
Years ago I also started designing an OSH mouse[1] as there was nothing on the market (in comparison to OSH keyboards). The main problem I encountered was mechanical design, as with 3d-printing it is hard to get a good mouse-wheel with vertical scrolling. The same goes with the other mouse buttons, where you also want good tactile feedback.
KiCad 7 will get power and signal integrity tools. In fact, there is already a branch with working DC power integrity simulation prototype (current-density/voltage-drop/resistivity) where you only have to specify a board and all ports with their constraints.
I'm the creator of the Altium importer in KiCad, and yes, importer development is time consuming but important for people without access to those programs. I even looked into Allegro and reverse-engineered initial bits, but without access to those programs it is practically impossible to write something meaningful. At least for Allegro, you can export to Fabmaster and import it into KiCad.
It's also easier to write importers for the ASCII file format than for the default binary file format, but for the former one the user needs to have access to the proprietary program to export it, which makes them unsuitable for some use-cases.
And the latest moves from Altium will promote growth in the professional market.