I’ve been studying Portuguese for almost two years. By fifteen years, I obviously hope to be fluent.
I do have an English-speaking friend who lives in Brazil, and she complained about her (mandatory) English teacher not pronouncing the words right, but I happen to be a native speaker, so I probably would pronounce them better than her teacher.
I’ve only met one person who spoke Portuguese where I live, and though I would be put through a less complex process to just stay in the United States, I’m not actually sure how many people would come.
For example, in Chicago, there are Polish schools, which are definitely more useful than Portuguese classes.
I do notice people on the Internet from Brazil wanting to get better at English. IF I end up following through in 15 years or so, would it be better to teach in Brazil?
The market for Portuguese language teachers in the US would depend heavily on where OP lives, and they might have better prospects moving to a different city. I would think a large city like Chicago would have some demand, but perhaps not as high as Miami given the population of Brazilian expats and tourists in Miami. And either of those would probably be higher than, say, Crosby, North Dakota unless Crosby quietly has a large immigrant community. Still, moving within the US for work is probably much easier than moving from the US to Brazil.