If we wanted to digitize all ancient texts, what would it take? How many are there? Starting at the beginning of written history ~5,200 years ago to ~2,000 years ago, how many texts do we have from each millenia or century? Are they accessible to be digitized?

What about earlier symbols and similar potential communication? For example, caves sometimes have marks that seems to have some symbolic meaning, such as slashes that seem like counts. How many are there to digitize?

I'm curious about the scale of it.