Most cases for whom? There are plenty of fields in which being cpu-bound is the norm rather than the exception. There are a whole load of assumptions that go into any general advice like this, consider making fewer of them today!
That's like objecting to the statement "Most people have two arms, two legs and one head" by replying "For whom? There are plenty of demographics, such as amputees, where having a different number of arms or legs is the norm!" The fact that unusual things are normal for some subset defined by those characteristics is tautological. It doesn't make the general statement false.