IMO, theory or music theory in particular is frequently misrepresented to be a linear meta state: i.e. an unbreakable rule that governs all things, and judges all things. One of my teachers in grad school encouraged his students to think of theory as an interpretation, as one person's view or explanation of how a particular thing worked. Just as many performers interpret a given piece of music differently with perfectly convincing results, so to can ideas of a theoretical nature be interpreted.
I think it is unfortunate that all to often performers and musicologists self-segregate themselves into their own camps. So much can be gleamed by examining alternate perspectives. Yet there is a tendency for people to gravitate to an activity that is familiar and that brings comfort. Ultimately it is knowledge itself that suffers from this course of action.
To the OP's inquiry. It is not necessary to study past theories in order to come to an understanding of a topic. Knowing what has been previously written and though out can give context - certainly it will assist a person in gauging if they are thinking up new ideas, or just trying to reinvent the wheel so to speak.
There are certainly excellent performers that are also inquisitive academicians. I've come to know quite a few such people.
However, there is a flip side: people that can endlessly engage in academic discourse, giving the impression they know a whole lot about something, boldly flaunting their virtuosic prose; yet almost never touch an instrument, utter a sung syllable, attend a live performance, or open their ears to a recording. One would caution against going to that extreme, but these kinds of people do exist.