Many universities require 2 years of a foreign language as a prerequisite to graduation. Spanish, French and German have been popular choices. However now, most universities offer other languages as well, and a student is generally able to pick which one to concentrate on.
Many Americans and non-Americans who live and work or live and do other things in the USA, speak their native language for everything that they need to do in the USA. Many Americans, native or otherwise are not fluent or functional in English. Some of those are native born, but most were born and raised outside of the US.
Most Americans who don’t have not an academic or economic requirement to study a foreign language don’t study Spanish or any “foreign language”, don’t learn any foreign language.
My father studied German because it was the common choice for people going into medicine. Others of his generation might have studied Russian because they majored in mathematics.
Later my father studied Spanish, years and years after pracicing medicne, for pleasure, as a challenge, and maybe because it was useful from time to time in his practice–patients, family members of patients, hospital staff, when traveling to predominantly Spanish-speaking countries.
As you experienced, English was the language you needed to do what you wanted to do in the USA. However, you did encounter people, circumstantially, who did not speak English, such as the cleaner/housekeeper that you mentioned.
In my opinoion, outside of need to know a langauge other than English (for profession and/or academis) , most native speakers of English who reside in the USA do not work at acquiring/learning any other language.
The reasons are usually academic or work related or even family related but, rarely just fore the helluvit, so to speak.
An American living in the USA might marry someone whose parents don’t speak English, so they might be inspired to learn the language that his or her inlaws speak. An American living in the USA might want to know a foregn language that members of his or her non-English family members speak.
As an adult, learning/acquiring a foreign language has to be more than a phrase book when traveling, more than a whim. It takes work.
Most English speaking Americans do not work at Spanish out of curiosity. Nevertheless knowing both Spanish and English are advantageous for anyone living in the USA.