IF is actually very binary, you just don't eat when you're fasting and eat whatever you want when you're not. (But try to keep it under 600 calories if you're a man, 500 if you're a women. And of course the healthier the food the better, think fish, greens, etc.) It's that simple.

I like OP's point, this diet works and it can't be sold to people en-mass which causes confusion when different retailers put their own little spin on things. Most fad diets are confusing, hard to follow, and sold to you. IF is none of those things.

I think you are underestimating the capabilities of marketers to create products and then selling them. I also don’t think IF will be healthy if people eat whatever they want during non fasting time.