Probably like Ecuador or Bolivia. There would be no US to break into to find jobs and live better.
Did you ever wonder what the US would be like without Mexico on its southern border. What if we had another English speaking nation like Canada on that border. I know, no produce pickers, no gardeners, no housekeepers, etc. Just maybe we here in the US would be a lot better off. At least our Federal and state governments would not be spending hundreds of billions of dollars every year.
Another English speaking country on our southern border would be nice? As for produce-pickers and landscapers? Americans, the same folks who’ve always did it before Mexicans invaded. I never picked produce but I have done landscaping. Hard work never killed anyone. Imagine if in 1848 the United States decided to stay in Mexico. We’d be a super-giant country and Mexico wouldn’t be such a mess.