Even though Telmex (his landline company) was acquired from the state, and therefore was a monopoly from the start, Slim faced a monopoly by Iusacell on the wireless phone industry, which he managed to break and manage to get Telcel (his wireless company) to become a monopoly basically by making people want to switch.

Slim's story includes several investments on different industries, including specialty shops (Sanborn's) which he has managed to completely turn around from near-bankrupcy to huge commercial success.

I am not making a claim that his wealth from Telmex didn't contribute to his success, but implying he just managed to get where he is because Mexico's regulatory bodies are useless is a huge understatement to his ability in an industry where several key players (Like AT&T, Nextel, Telefonica Movistar, and others have failed).