Yes you can get an FAA ATP flying nothing bigger than a piper cub basically
Bull Cr**, to use an Americanism. You can get a single engine ATP in the states, but is is not going to be in a "piper cub". More like a PC-12.
In the United States the ATP serves as the graduate degree for
professional instrument flying. Be it in a scheduled airline, a corporate job or charter. And there is nothing wrong with that. Europe should wish that its aviation industry was a vibrant.
Good airmanship,
judgment and instrument skills can be found in people from a range of backgrounds. And the best airlines try to employ all of them. Anyone surrounded by like minded clones is
professionally stunted, and I feel pity for them.