Time Travel, proving that the grandfather paradox is fake?

I heard someone say that if time travel was possible, we still wouldn't be able to do it because of the grandfather paradox. Now, for those who don't know; that's when a person goes back in time, and because of his deeds, it leads to him never being born; people have said that by even kicking a stone out of place it would snowball into a different future. So I thought this over, and realized that its impossible for that to be true. Think of this: Keven goes back in time and he meets two people, he introduces them to each other; these two people make a huge invention, lets say the TV. So without Keven, the TV wouldn't have been created. This also means that its impossible to rewrite the future even by visiting the past, so if someone time traveled into the past, they would change nothing. What does everyone think of this?