Very interesting, I don't know about the person or the factory, just have a comment on his name as written on the picture.
As English has Vienna for Wien, in Hungarian it's called Bécs, it means Fancy (place).
On the picture it's written as Bétsy with old Hungarian grammar. In it, the letter "é" is a separate Hungarian letter, the "ts" letter combination was a separate letter in the Hungarian alphabet, now it's "cs" and sounding like "ch". Finally at the end, the letter "y" is a fancy possessive affix, attributing to that person belonging to that place, like a New York(er).
Combining the above with the tradition, that the most talented crafstman gravitated to Vienna in the Monarchia, in my opinion Bétsy wasn't his original surname, but as a business name first, in it preserving his Hungarian heritage, than in time become his new, real name Emerich von Betsy, as some websites showing it.
If I may ask, what's your interest in it, do you own one of his pianos? I saw the price range from 3-5 Thou.