We obviously are very strict with the 5 grains on Pesah, but we do eat food made with them, namely Matzah. And with the exception of the issue of "Gebrochts", we do allow Matzah to be re-engineered into other foods.
Yet, when it comes to Kitniyoth, it seems that we are more strict. I have never seen corn chips, for example, for Pesah (for Ashkenazim). Yet most mainstream producers of chips make a baked (not fried) variety. I don't know anything about the potential composition or taste of such chips being ground back into meal and used for baking, but that's because I've never seen it done, either. Would it not follow that, for Ashkenazim, Kitniyoth baked into chip form (or tortilla form or taco form) following the same procedures as for Matzah should be acceptable (and potentially re-engineerable into other foods)?
Why are we so strict in this regard?