Why does a balloon filled with helium stop rising over time?

According to Archimedes’ law, the pressure forces of air gases will act on the surface of the ball with helium, the resultant force (buoyancy force of the gas) of which will direct the ball with helium upward. But since with an increase in height from the surface of the earth, the air becomes more rarefied (the air density decreases), the helium ball will stop at the moment when the air density becomes equal to the total density of the helium ball.