Frito Pie isn't food. Frito pie is ambience. Texans, generally regarded in New Mexico as lacking in aesthetic sensibility, cannot be expected to understand this.
The Woolworth's in question was located right on the ancient Plaza in downtown Santa Fe, New Mexico. Teresa Hernandez' trademark wasn't so much the Frito Pie, as the way she served it: she cut off the top of a bag of Fritos, added some shredded cheese and poured the Texas-style chili right into the bag. You would then take your hot bag of Fritos out of the Woolworth's to the Plaza, and watch the scene: tourists buying turquoise and silver jewelry from Indians sitting under the portal of the Plaza of the Governors, kids skateboarding, low-riders circling endlessly, and so on and so forth.
You haven't had a Frito Pie until you've eaten one out of the bag on the Plaza.