Chinese takeout is a popular American dish, but just because it's easy to find doesn't mean menus can't differ greatly.
Comparing Chinese takeaway in the U.S. & China yields comparable results (via Insider).
Chop suey and chow mein are based on Chinese recipes but have been adapted for the American palate.
The first wave of Chinese immigration began in the mid-19th century, but the popularity of Chinese food didn't take off until the 1960s, according to the BBC.
This allowed professional Chinese cooks to enter the U.S. to set up shop & expose Chinese food to the wider American audience.
But also had certain consequences, most notably replacing traditional dish with Americanized innovations like General Tso's chicken & crab rangoon.
Why chop suey & chow mein? Chop suey is a dish cooked with leftover veggies like celery, carrot, bean sprouts, & anything else was available.