What do we really need scientific theories for?

In Steinbeck's novel about a family of inventors, "East of Eden", it is observed about one inventor "Like all true empiricists, he had a horror of theory." This could equally be said of Galileo Galilei, who was persecuted by the Holy Inquisition specifically for failing to develop a theoretical alternative to the Ptolemaic System of the Universe, while trashing it completely, in favor of Copernicus' Sun centered view of things. Galileo loathed theory, all theory, and even failed to get his University degree specifically because of the emphasis in Universities at this time on the world's first great theoretician, Aristotle, who Galileo thoroughly detested. Galileo was an empiricist, he believed in mathematics and data, and so no need to make assumptions, so no need to speculate about absolute universal rules for anything, since such could never be proven, and represented restrictions on freedom of thought. Now, of course, there's a very good reason why governments and powerful bureaucracies like theories. They like rules, they like structure, they like power. Truth itself is unpredictable, and doesn't represent a very good basis for building powerful systems on. Currently, in science, Einstein's Theory of Relativity represents the Gold Standard of theories. A total model of the Universe, based on the incredibly simple mathematical principle that nothing can possibly go faster than the speed of light. And this brilliantly explains the wave properties of light in a vacuum. Einstein tells us "When you ask simple questions, and the answers are also simple, you know you hear God thinking." Of course, when you ask simple questions, and the answers are also simple, you may be oversimplifying. And, that's the big problem with theories, in general. Anyone questioning Einstein's Theory of Relativity these days is ridiculed as a "flat earther". The evidence for it is described as "overwhelming". Physicists will claim that it could only be "added to", it couldn't possibly be overturned, just like Newton's model of the Universe wasn't "overturned", just added to. Is Newton's Principia really a "theory" at all, or is it just a summary of data? Other than Universal Gravitation, which is something people have always been aware of, one way or another, there don't seem to be any assumptions in Newton's conceptions at all. In contrast, the average person still has no particular impression whether light is an absolute limit, or not. Sure, GPS is now cited as evidence, by engineers, but all GPS shows is that gravity has very small effects -- microseconds on the hour -- on atomic clocks. And, in general, gravity can affect clock mechanisms, without affecting time itself. There's other evidence, but, it all can be easily dismissed as confounded. And, now, with Dark Matter, we know that the vast majority of matter in the Universe doesn't even interact with light, at all! But, have we found any Dark Matter particles that actually travel faster than light? Is anyone really looking, or would they accept evidence, so inconsistent with the magic of Albert Einstein? Galileo recognized that scientific theory could blind people to reality, and discourage them from looking at what was really there. But, power structures love theory, don't they?