Your analogy of comparing Google’s efforts of digitizing books to the seizure of someone’s house and car is not equivalent. There is a fundamental difference when it comes to digital goods and physical goods. Digital goods are, for all intents and purposes relevant to this discussion, infinite. Physical goods are finite. Houses and cars are also private property, books are not.
A better comparison would have been to compare books to a business. Google’s efforts of digitizing books would be equivalent to Google walking through the aisles of a Best Buy or Barnes & Noble with one of their street view cameras. Where users of Google could search for an item and see which store has it, where in the store it is, and the price of the item.
There are only two ways that Google’s digitizing of books could impact an author’s profit. The first would be if employees at Google were accessing the full digitized book for personal use instead of purchasing a copy. If you have any evidence of this, then you should pursue legal actions. The second is if an authors profit is primarily made by deceiving readers. By allowing people to search for books which contain information they are looking for, a person is more likely to find and purchase the book most relevant to them. This would reduce the number of books a person would buy only to find out that the book they bought contained no useful information to them.
For the record, I do not believe the majority of authors are intending to deceive readers in order to make sales. lf authors income are in decline it is due to societal factors well outside of Google.