D&D does not attempt to explain the physical nature of the universe or how magic works in any great detail, any more than it attempts to get you to calculate the number of newtons that a person undergoes after falling before calculating the damage.
I don't know what the intent was. All I'm doing is looking at what is provided and trying to come up with some coherent description of it. If we accept four elemental planes and wizards can cast magic by chanting words to say nothing of giant spiders, then the universe that D&D exists in is not the real universe because the laws of physics prevent that.
What is natural to an inhabitant of that universe would be very unnatural to us.
What I think we would find is that at different points, different writers have provided different ideas about how the D&D universe worked because D&D never has undertaken to set out a coherent description of how it works. We all agree that there is some sort of gravity, but there is no reason to assume it obeys the law G*m1+M2/r^2. D&D doesn't specify, so if you want to think it does, then fine, but then you are left with the problem that how does the magic work.
Look at it this way. I think we all agree at some level that as a fighter levels up, his reflexes, his evasion, his speed in combat, and so forth are increasing incrementally. We know that because if we've done any real fighting at all, we know that there is a limit to how "good" you can be without increasing in fitness. You can do a lot with skill in tennis, but at some point if your ability to cover ground and strike the ball hard doesn't increase, you won't get any better and you'll be destroyed by people with more speed and faster reflexes.
So there is exists some point in the progression of a fighter leveling up incrementally where they are as fast and skilled with the blade as it is possible for a real person in this universe to be. If they at that point gain one more level, then what they are doing is at that point superhuman. After that point, they can do things like wrestle 2000lb grizzly bears with their bare hands and the bear is at a distinct disadvantage. This is something D&D fighters can already do, that real world people cannot. The point where it happens may differ between systems, but it eventually happens in any system. The fighter's hit points and combat ability eventually drown out the bears obvious natural advantages over a human.
So if that is "magic" then in D&D it is already happening. But here is the real crux of it. The people within the D&D universe already live in a universe where some humans get to the point they can wrestle a bear and beat it to death with their bear hands and come out of it with just a few scratches. Our idea that this outside the realm of the limits of human ability comes to us from our bias as outside observers talking about what humans can do in this world. But a commoner in the D&D universe doesn't describe wrestling a bear and beating it to death with your bare hands as outside the limits of human ability. In his world, people can already do that.
I'm putting it to you that historically, D&D has typically assumed that our ideas as outsiders of what is the limits of human ability are reached at about 5th level. Then D&D just keeps going from their incrementally. In the real world, the peak human ability in the long jump is about a meter less than what a kangaroo can do. Whether or not the two things are comparable isn't really the point. If the triple jump is more your measure of comparable jumping ability, then the D&D universe is still one where peak human jumping ability might incrementally reach and exceed real world peak human jumping ability as characters level up in skill in jumping in the same way that the D&D universe is a universe where peak human combat ability levels up so far past peak real world combat ability such that if we were to watch a D&D fighter in combat moving with uncanny reflexes and blinding speed we'd think it was supernatural.
