Actual question for anyone who may know...
At what point in human history did "Theory" become a replacement for "hypothesis"?
There is no flat earth theory. It's a flat earth hypothesis.
Or is my definition of theory too scientifically inclined?
Theory
a supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained.
Hypothesis
a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.
Model
a representation of an idea, an object or even a process or a system that is used to describe and explain phenomena that cannot be experienced directly.
You can have a Flat Earth Theory (it would be empirically invalid), as it would explain many phenomena, although incorrectly, The same way Astrology is a theory that the movements of stars and planets govern human behavior. Wrong, but still at Theory.
In my opinion, most social science "theories" are wrong, and one should stick with models, a more humble approach.
For example, in economics General Equilibrium Theory is invalid, for one thing all the assumptions required have been empirically shown to be violated to some extent. However, as a Model of how an economy could coordinate between markets, it's invaluable. The problem is it is treated like a Theory, and the results of Computational General Equilibrium Models as if they're accurate representations of the real world instead of back of the envelope estimates. A good example of intellectual hubris.