If that's the case then maybe we can write a program that scrapes 1% of 100 books every day. After 100 days we will have 100 books!
2: This is not Google's first rodeo when it comes to scraping. I'd be surprised if you got more than a few days into the described process, so no, it certainly does not scale.
So after 100 days you'll probably still have 100 incomplete books.
Google actually thought this through.