this is true, and one of the biggest challenges large firms face is bringing the right talent to a project. A large firm likely may have at least one of every type and flavor of designer, but if they are tied up on another project when the perfect program comes in for them, someone else who may be less suited will work on it. Not necessarily less talented or skilled, but less suited, and the result won’t be what it could have been.
This gets to the age old question, can a great designer design anything?
My short answer: yes
My long answer: No. While a great designer theoretically could design anything, so much of finding a great solution is being passionate about the problem and the space you are working in. So while a great designer literally could design anything, there is going to be a huge swing in the quality of the output as it aligns to things like experience and skill, but more critically interest and passion.