While I agree with crote's reply that this isn't a limitation at all for a professional, I'm surprised to hear your opinion. Of all the libraries that come with tools, I find KiCad's to be the highest quality with regard to footprints (in addition to having a ton of them available). Perhaps the symbol libraries are more limited, but that being said, I've never found a mistake in KiCad's library. I've definitely found mistakes in the built-in Altium libs. To be fair, Altium started getting much better after their acquisition of Octopart, and it started to be easier to find things through the built-in search.
As a professional that lays outs boards about twice a year…
I have never understood the concern about the built in library. Professionals barely use it. You MIGHT use it for some SMDs, but that’s about it. Everything else you are going to get or make or download the specific footprint.
I agree with the parent comments. You will spend an absurd amount of time making library components, and you can't trust 3rd party. The 3rd party sites are a great starting point to take out some of the grunt work, but you need to tweak them.
Your (cad tool) component library is your most valuable resource, and in my opinion more valuable than schematics/layouts. You have your own proven set of components that you know will work in manufacturing. Even the standard passive SMD footprints need to be tweaked for your specific requirements (ISO, design for manufacturing etc).
In regards to Kicad... great tool for 90% of designs. I would say as a rule of thumb, if your design can be manufactured at one of those online, cheap PCB manufacturers (for say, $10-$20) then Kicad will cover it. Once that calculator tool starts going higher you're probably doing someone more complicated that warrants the more expensive tools.
