And while they do make progress, even after two decades on almost every indicator they are far behind the native born population, as well as immigrants from every other country. (And after here twenty years, their welfare rate INCREASES).
"So when compared" to not just Canadians and the British Kingdom, but also compared to South Koreans, Chinese, Filipinos, Russians, Indians, and Arabs. Unfortunately, not a huge surprise.
There is a very simple explanation for this:
All the nationalities that you mentioned above need, by force, to come to the USA by air travel. That means, you will:
1. Need to apply for a visa at a US embassy before any airline will even sell you a ticket
2. Show the visa at the point of entry to an immigration official, in this case, at an international airport.
Now, maxparrish, I will give you the benefit of the doubt so instead of assuming you are a bigot I will asume you say all these outrageous claims about Mexican immigrants out of ignorance and perhaps a few purely anecdotal bad experiences with Mexicans (such as getting diarrhoea for eating tacos)
First of all, getting a US entry visa is not that easy. You need to demonstrate to the US consulate that you are capable of paying for your expenses while in the US, so you will first need to show that you have at least a few thousand dollars in a bank account, as a minimum. Also, your age, marital status and education level play a huge role in whether you get a visa or not. Then, there is the cost of the airplane ticket. To come to the US from all the countries you mentioned will cost you at least $1000 in economy class.
I am sure that by now you will realise that all these obstacles mean that only very few within those countries can come to the US. So the Asian, Middle-Eastern and Eastern European immigrants that you see here are mostly:
1. Educated
2. Wealthy (At least by their home country standards)
Mexicans and Central American on the other hand, can come here by land, and do not need to get a visa in order to board a plane. They just take cars, buses or trains to come to the nearest town across the border and then cross on foot. This is the reason why you do not see hordes of Chinese and Indian farmers coming to the USA, but you see hordes of Mexican farmers coming in.
The fact is that the US needs them. As someone else already said: Who do you think builds the houses? Who cleans the office buildings? Who makes the hotel beds?
What the masses of Germans, Irish and Italians were a hundred or more years ago is precisely what the Mexicans, Guatemalans and Salvadorans are now. The Irish and the Germans came here by boat using the transatlantic behemoths that no longer exist. The Mexicans come here by foot.
The prejudices you have fallen for already existed back then. Do a quick search about how the Irish were stereotyped. Just like the US gets scientists and doctors from India today, there were probably English doctors coming in first class aboard the Titanic while on the decks below the Irish farmers and factory workers were crowded in third class.