Without having to choose between the theories accounting for the formation of the Earth/Moon system, it's long term stability, based on the gravity /energy balance, is enough to allow life to flourish and evolve. Obviously, Gravity in our system works just fine. The present theory is about spin and orbits, and gravity dominates both. The OP's alternative theory proposition pointed to the possible local effects of the outer gas giants of having sections with zero orbital velocity and later o double orbital speed . but Applying the formula (Vo ; Vr) xR to the inner planets showed another intriguing connection in rotation, orbital, distance relationships. The moon pivots around the earth so to speak, showing the same face all the time. but more surprising, the Earth too, rotates in such a way that it would pivot at the Moon 's distance as seen during a new Moon, an eclipse. To come back to the wheel analogy, at present, the Earth rotates as if it "rolls" when considered fixed on an imaginary dik, with radius of 400 000 km , the distance to the moon. gravity has done it.