In one way, many newer editions of textbooks are worse than older ones: the printing. That's courtesy of modern print-on-demand systems, where instead of sharp offset printing you get glorified inkjet output that's noticably blurry. And instead of a bulletproof Smyth-sewn binding, your "hardcover" book gets you a short-lived perfect-bound paperback glued into a hard cover.
When it comes to buying textbooks, unless a newer printing has corrections that I care about, I'll purchance an earlier printing to get the better book.
The problem is that the cheap books have already had their signatures cut into individual pages so that they can be perfect bound, basically running a strip of hot melt glue down the binding edge. At this point, you cannot rebind the pages in a way that will compare to the strength and durability of the original signatures.
When it comes to buying textbooks, unless a newer printing has corrections that I care about, I'll purchance an earlier printing to get the better book.