[notahacker]

I'm not sure English would have "retracted back to the UK" even if the US spoke Navajo as its preferred language. It's not realistic expectations of doing business with the US or watching Hollywood instead of Bollywood that explains why English became the alternative to Hindu dominance of language in Indian education, commerce and civil service. The much earlier decline of Spanish colonial influence didn't diminish the pervasiveness of its language in certain parts of the world (most where English is seldom spoken) in any meaningful way, and there really aren't any obvious corners of the globe English hadn't already spread to some extent before American cultural influence kicked in.

There's a reason why people haven't been aggressively learning Chinese despite it being the language of the world's #2 economic power, and that's because all the boots on the ground work to set up civil services, education systems and trade networks and associate their language with prestige and power had already been done by colonialists speaking other languages.