They don't have different oil channels. They just have to bow to market availability. I would wager that the engine failure rate is far higher in Mexico though this isn't directly related to oil viscosity. I'm not familiar with all of the intricacies of Mexican climate but am guessing they rarely see freezing temps anywhere and the climate is subtropical. So they have to worry a lot less about startup wear from acidic compounds as a by product of the combustion engine on a cold day...
In any case I'll take a 0W-20 using (mostly) GTL or POA combined with ester than whatever 5W-30 is offered up in the great republic of Mexico.
I also recall Japan being the gold "thicker oil" standard with comparisons up until less than a decade ago when they went ever thinner than the US...