Why Does Gravity Get Weaker with Distance?

Because it "radiates" spherically. Then just do the math.

Observed Law in the Universe. Start from Isaac Newton and follow ...

I was not proven to be otherwise.

Why the speed of light is fixed and is a limit in the Vaccum?

Because in the universes where it doesn't, people can't get off the floor to reach their keyboards.

Lookup "Inverse Square Law" as alluded to above!

The distortion of space-time becomes less as the distance from matter increases...as gravity is a function of the distortion of space-time caused by matter, it too becomes less.....

It's difficult to soar with eagles when you work with turkeys.

The gravitational field around the center of the object doesn't change at all, it is just less strong as you move away from the object, by the inverse of the squared distance, but this happens only when there's someone there to witness it .

'...but this happens only when there's someone there to witness it....'

.

The large mismatch between the limited number of 'someone's and the infinite number of 'there's suggests otherwise. There is good evidence the approximation has provided good correlation for places where it is highly unlikely any someone has been to observe.