Plus you have a weight limit, size limit and underpowered motors. The closest I think we will ever see in the Alliance era was Beatty '02 (probably CD '98 before that). It scored all 3 goals almost all the time and it was mathematically impossible to beat them if they did. Even they got Fluffied (180) in the finals. There always is a robot, group of robots, or strategy that is your perfect foil.
We will never see an unbeatable bot. The rules and ever-expanding level of competition are stacked against it.