If all normal daylight really came from a "point source 93 million miles away", you would see many different things compared with the way they are.
For example, the sky during the day would be completely black. Shadows on the ground would also be completely black. At sunrise and sunset, the light level would change from "normal" to "pitch black" in a few seconds as the sun disappeared below the horizon. If you were in a room in a house where the window was not facing the sun, it would be completely dark all day. And so on. You can get some idea what that would be like if you go outside on a dark night with only a torch, or the headlights of a car, providing illumination.
In reality, much of the light which reaches the ground is diffuse light which is scattered by the atmosphere and arrives equally from all possible directions. If that amount of light is enough for a plant to grow properly, it will not "grow towards the light" because the light is coming from "everywhere". Of course some plants do "grow towards the sun" to some degree, but the sun is not in the same position in the sky all day!
This is completely different from a grow-light which is not really providing enough brightness, and which is a single fixed light source which the plant can grow towards to try to get more light. The plant doesn't "know" how far away the light is. It just "knows" that it isn't getting enough light, and the brightest light is coming from one particular direction - so it grows in that direction.
You can see this in an extreme way if you try to store vegetables like potatoes in a "dark cupboard" which is not completely dark, because some light is leaking in around the door. If the potatoes begin to sprout, they may grow sprouts several inches long, pointing directly towards the small amount of light that is getting in.