I think the solution (and again, the technology appears to be out there, I just don't have it) is to create systems where you can mark your place on a DVD or CD. The only problem there is, like rewinding, the renter has to remember to unmark the DVD or CD before returning it to Netflix or the library or wherever. Otherwise, the next person who watches it will be carried instantaneously to the scene with Frodo and the eagles or the blowing up of some ship or whatever.
On a completely different subject, does anyone actually read the blurbs on the backs of books? Not the summaries but the parsed out quotations of reviews by famous people? I don't think I've ever bought a book in my life based on those quotations. Perhaps, they're like eye candy. We expect them to be there, but nobody actually reads them. In any case, what do we expect them to say? "This book is kind of good but I didn't care for the middle." Or, "Read this book only if you have absolutely nothing else to do." Maybe the quotes do say that, and nobody reads them closely enough to know it. (Actually, occasionally I have looked to see who, rather than what, reviewed the book, but that's usually after I've already started it.)