You can throw a ball to "prove" Newton's laws correct.
No, you can't, or we'd have his laws in antiquity. Beng able to measure the ball's momentum and reaction to gravity isn't as simple as you think if you start from scratch. I mean it took a lot longer to get to it form teh invention of maths then it took to get from Newton to modern science.
Plus, we're talking abut the evidence itself, not the effort it takes to obtain it (like it's easier to see if someone is living in the house next to mine, then in a house atop a high mountain 1000km away, the evidence is still a person being there).