Because of the private near-monopoly of Telmex, telecoms costs are much higher too.
Add in the extra infrastructure and telecoms costs, and the savings are still in excess of 30%.
No wonder Mexico has some of the highest telecoms costs in the world, driven by Mr Slim.
The savings may grow, because India's telecoms costs, which are higher than in rich countries, are falling thanks to liberalisation.
That question is all the more pertinent because telecoms costs in Mexico, though falling, remain above the international average (see chart 5).
But smaller ISPs, who are aggressively passing along telecom cost savings, have an aggregate 50% share.
"It's not because telecom costs are too high.
"Not only does it improve the customer experience, it helps us decrease our telecom costs a bit, because when someone is on hold, that's on our dime," he said.
firm that manages telecom costs.
That's assuming 30 hours of monthly usage per customer, with telecom costs of 15 cents per hour.
