"if the oportunity of changing the rules is given" 

What are you talking about? No one needs permission to fork Bitcoin. It has happened many times, and will continue to happen. It's just a question of how much of the bitcoin economy forks away. It's part of the game theory.

Bitcoin is a consensus of humans, and they express their will through the code they use to validate their coins. If there is a big break in consensus, a fork will happen. You can't stop it.