That relies on a rather specific definition of knowledge. Thomas Sowell has done a lot of good writing on these topics: the nature and varying definitions of knowledge, the role of academics and intellectuals, etc. It's ironic because he doesn't like them much despite being one himself.

Conservatives tend to place more emphasis on earned experience than liberals do. Experience and "book knowledge" are both different aspects of the concept of knowledge, but it's certainly untrue that universities teach everything that could be called knowledge. Indeed they're famous for not doing so, hence the fact that "it's academic" is an insult not a compliment.

Whether this means conservatives value experience more than book knowledge is unclear, it may be that they consider both important whereas liberals consider experience relatively unimportant and thus cluster in academia.