Anyhow, there have been many "good enough" languages — mostly, it depends on cultural factors. Latin is still present in today's traditional sciences (biology, medicine,) French is the language in arts and cuisine, Italian is dominant in music theory, Greek infests philosophy and logics, as does German, which also has a strong foothold in engineering and mathematics. And what do we learn from that? There is no one language. There cannot be one. At least, we haven't figured out a way.
Over time, dominant languages rise and fade. That's why I loved Firefly for incorporating Chinese :-D English will fade (most probably.) Also most probably, it will stay in the computing sector, just like Italian did in the music sector.
> there are more students taking SATs in China in ENGLISH than in the US+Britain
Yeah, that's like saying more Indians write Java code than Americans. What does it mean? Java is "good enough?" For some tasks, but not for all.
That Rome to WWW line of yours is quite eurocentric. Can't put my finger on it, but "American web pages" look different in Asia than they do in the West. The cultural values of ancient Rome had no real influence there — except you mean to imply Babbage influenced C#.
My knowledge of LISP doesn't go beyond programming-book examples. I somehow never got into it — I blame Haskell!. But you're certainly mistaken that language recognition is sequential. For all we know, it most likely isn't. And for Chinese, for example, it really definitely isn't. Reading a Chinese poem is reading backwards, across, down, and up at the same time in order to get the full meaning.
I don't get how LISP is closer to natural languages than to programming languages?
Anyhow, my take on the situation of the OP: if he stays in the sector he's in and doesn't move out before retirement, he's found his last language. Otherwise, different tasks and developments are going to force him to adapt. There is no one best language. We've been trying to find it for thousands of years, and it's been rather fruitless so far.