Why doesn't a ball roll on forever after being kicked at a soccer game?

Because it has different forces causing it to stop, like the grass causes friction on the ball causing it to slow down and stop

There are many factors affecting the ball. To name just a few, wind, friction and gravity. The friction between the ground and the ball slows it down. The gravity pulls it towards the center of the earth which eventually makes it stop. The wind could slow it down or speed it up. All of these forces with the help of more factors make the ball stop. The strength of the kicker also affects it.