yitayningwut-“It would make sense that they had music sheets. They probably just got lost, that’s all.”
That’s all? You’re just proving our point. If the music sheets got lost, then the tunes got lost over the past 2000 years.
By the way, did your family preserve the tunes that your great great grand father sang a hundred and fifty years ago? Most tunes get lost over relatively few years. Many zmiros from the 50’s and 60’s aren’t around today, and that’s the way it’s been; the old makes way for the new.
I’ve seen many nigunim and wedding music change and conform to the times. A drei here and a drei there, and after a while you’ve got a new and changed tune. So it’s highly unlikely that Jews being the creative people that we are, that we allow anything to remain the same unless mandated by halacha.