For all of us descendants of immigrants, if our earliest ancestors arriving in the US were held to a strict standard of having fluent English and immediately marketable, in-demand skills, how many of them would have been turned away?
Answer: Most
I have a line that came from Italy in about 1920. My great grandmother never spoke a word of English because she never had the opportunity to encounter English speaking people on a regular basis. Her husband spoke English because he went out into the larger community. In order to survive some immigrants opened up food shops (delis, butcher shops, bakeries, restaurants) to cater to their own communities that would speak the language.
That said, the population was 108.5 million in 1920. If you were a guy or even a female then you were competing against children working in factories. So, mines, factories, farms, slaughter houses. Not necessarily skilled work force and it served to lower wages for the native population at the time. There weren't a whole lot of people that graduated high school. Before 1920 the factory model, like the Gary Plan, was in use in about 200 cities. The business community wanted kids to learn all about moving at the sound of a bell and pretty much operate like an assembly line.
Today when we look at immigration it is far more difficult to teach English to someone that is not literate in their primary language and due to the only English in the US crowd there aren't a whole lot of folks that can even speak/translate some of the other languages that we have.
Since the motivation is still the same (decrease wages) speaking English is really not relevant. It's a distraction.