The bold-face in the above quote is the more significant financial question: "How difficult is it to add new symbols and footprints to the existing libraries?". The great majority of commercial users of KiCAD - or ANY layout program - will create and maintain their own libraries. For every board I've ever done, whether on KiCAD or several of the other $$$K products, the "library work" has taken anywhere from 10% to 90% of the total effort. A proper financial evaluation of KiCAD needs to ask, "How much time, effort, and resources are required to create, document, and maintain the libraries?".
Well, I will concede the point on the inductors. Did you say 30 years? Old habits die hard: here in the U.S., the jagged line symbol is still the more common representation by a very large margin.
The jagged-line symbol is the only symbol I have used in KiCAD for almost 2 years now. (And, the symbol I used on more than 95% of the schematics I drafted with other EDA tools before coming to KiCAD.) On my machines, that symbol is called "R_US" and it lives in the "Passive_RLC" library. (I maintain my own local libraries.) I'm certain that I took it from somebody's KiCAD Library repository. I don't recall drafting it myself, and I would have been rather reluctant to do so during my early days with KiCAD. But I don't know where I got it. Can anybody help?