My conclusion to your question (which I also thought about years ago) is that McDonald fries are not like the french fries you get from other places. McDonald fries are McDonald fries, other places might have better tasting french fries but they're not like McDonald fries. Five Guys have awesome fries, better than McD, hell, a local bowling alley makes a crinkle cut fries that's out of this world, but when you want McD fries, nothing will substitute that taste and style.

When I was stationed in South Korea there was a Doner Kabab stand outside of Casey and they fried their fries in tallow and it legit tasted like early 90s McD fries! I seriously lost a minute on my 2 mile run from eating there as often as I did.