1) Overall cost
2) Kids can't tell the difference between a $20 steak and $60 steak so why would I feed them steak?
3) Kids prefer things like box macaroni and cheese over made from scratch macaroni and cheese, or as another example, they tell me they prefer the $8 deep dish Little Caesars to the $25 NY style pizza at local Pizza place.

If it just me and my wife we can find delicious food for under $20 a plate, but I'm willing to pay more if we are in the mood for it. I consider $30 a plate still be "affordable" but "delicious". With my kids, it is often more to their liking and better for my budget to stick to places under $15 a plate.

But then you have to factor in the food. I can go to 5 Guys for a delicious burger and pay almost $20 per person by the time I've had fries and a drink. Or I can go to Red Robin and do it for $15 per person and sit down and relax. I'd pick Red Robin over 5 Guys pretty much every time.