Nobody who has ever used Google Books would think that it's putting complete copies online. The results include pages with hits, plus pages around them. There are so many missing pages that books aren't readable.
So after 100 days you'll probably still have 100 incomplete 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.
Google actually thought this through.