There are some diferences between used books and used cars... Sure there are 30 years old cars which are still running, but a car rarely can change more than 3-4 owners... In the other hand a book can be read by hudreds and this will really affect the author benefits. But I do not see any reason readers to care about this... Don't want Your books to be read - do not sell them... You could rent them or invent some other schema... Traditional publishing dies anyway... e-books are replacing the paper more and more and selling physical books will decrease drastically... Software publishers are facing this problem from decades - borrow some experience from them instead of complaining. Readers are respecting the rules! If You don't like Your own rules anymore - change them.
In my opinion books and e-books must be totally free for readers. Authors and publishers must be sponsored by the government, even if this will lead to increased taxes. And must be sponsored based on the number of books READ, not SOLD.
And slightly off topic - a publishing company maintaining a free e-library
Reasons why they are doing this are intersting...