Nobody in America is going to wait an hour for food outside of the high-end restaurants. So, anything with "caramelized onions" would need to prep and store that step with the associated degradation.
The exception was my favorite cheesesteak place (sadly now gone--the owners got old and retired). The owner literally had a row of chopped onions that stretched the length of the grill. As he cooked he would keep adding onions on the far right while moving the entire line of onions leftward--so the onions that got used actually had enough time to truly caramelize. Similarly for the steak, just much faster. When everything got to the far left (steak with cheese (people who want CheeseWhiz could go somewhere else thanks), onions, bun) his wife would assemble the full thing.
It was a thing of beauty to watch them work. And the cheesesteak was glorious.
And now I'm hungry and craving a cheesesteak that doesn't exist anymore. :(
However, I also noticed in Montreal "caramelized onions" actually always meant caramelized onions.
So it's just really just poor terminology rather than a ploy to fool you.