Because they aren't worth consideration. Breakfast tacos have a better filling to tortilla ratio.
This absolutely depends on what ethnicity is rolling your burrito. I have had those terrible white rolled burritos that have chunks of tortilla that have to be torn off, and also have had those amazing mexican rolled perfections that leave no piece of the tortilla without some filling.
I disagree with the breakfast taco thing. Then again, my breakfast burritos are generally covered in home made green chile sauce and baked to perfection so it's pretty much an unfair comparison.
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