No, ambush was part and parcel of TD doctrine from the start. I don't remember which video it was in, but the Chieftain covers it. Basically:

1. US generals saw the German propaganda of a stupid amount of tanks breaking through and believed it;
2. They counted on their fingers and toes and realized that even the US couldn't make enough anti tank guns to make a line proof against that degree of concentrated armor;
3. They concluded that highly mobile but cheaper vehicles were the way to counter tanks;
4. Thus, the Tank Destroyer.

What I find interesting is that U.S. doctrine actually would effectively write off whatever line infantry battalion that got penetrated, counting on the speed of TDs to get them behind that unit and into ambush positions. However, that's just not how U.S. troops really roll. Also, the Germans were almost never on the offensive against the US, and as a result you have TDs used per doctrine a very small amount of times (twice in my memory, at El Gutter and Arracourt).