Thanks for very well-written post that succinctly gets to the heart of the matter. If you will, I'd like to further quote from President Calvin Coolidge since the words of this great Conservative harmonize with yours:
American institutions rest solely on good citizenship. They were created by people who had a background of self-government. New arrivals should be limited to our capacity to absorb them into the ranks of good citizenship. America must be kept American. For this purpose it is necessary to continue a policy of restricted immigration.
It would be well to make such immigration of a selective nature with some inspection at the source, and based either on a prior census or upon the record of naturalization. Either method would insure the admission of those with the largest capacity and best intention of becoming citizens. Those who do not want to be partakers of the American spirit ought not to settle in America.
This is from his 6 December 1923 address to Congress.
And how quickly that all went kaput with the Great Crash.