I think you’re right, because the Chiles are mild. I never thought about it, but there are thousands okay maybe hundreds of varieties of green chiles. And it is funny that these cans just say green chile on them. All have the same mildness and flavor - so are are likely consistent between brands.
I am opening an online spice business soon. And most of the spices I use consistently in each recipe are dehydrated chiles. So in researching, I have discovered there really are a lot of different varieties out there. And even more in the fresh ones, most likely.
I keep those mild green chilis always on hand. They are perfect for giving a tangy Mexican flavor in things like egg and cheese bakes, or cheese and refried beans bakes (great low carb casseroles, great winter morning brunches), without heat. But I also now keep the chipotles in adobo sauce cans too, because combined with sour cream, that is the sauce par excellence for fish tacos. Just combine in food processor and that’s it. So good. Spicy.