I don't agree with most things that Ralph says. In fact, I think many of his opinions and positions are just plain wrong. But, I have to say, I pretty much agree with his statement here. In terms of playability and sound, the current process for mass producing basses can make some amazing instruments. With CNC used to do a lot of the cutting and carving, necks have gotten very good and very consistent. A $500 bass can be spectacular in terms of sound and playability. It can even be pretty nice looking.
Is a more expensive bass worth it? That is up to the purchaser, but there are things you can get in a more expensive instrument that you won't get in a $500 bass. That is about the price where the metal parts start getting a little better, but you have to watch out for easily stripped screws, bridges that buckle from the tension of the strings (Ibanez!), and frets made of a fairly soft alloy. You also get less by-hand attention to frets, so fret sprout is more common and the bass may need some fretwork to get it set up to its full potential. All of that can be done to a $500 bass and still be a lot cheaper than a $5,000 bass.
What you really get out of a more expensive bass is up to you. Maybe you just get bragging rights. Maybe you get an instrument that is unique to you - built for you and to your specifications. Maybe you appreciate a master craftsman's woodworking skills (Fodera). Maybe you like a nearly perfect fit and finish, or an instrument where every aspect of the design has obviously been carefully thought out(Dingwall). Maybe you finally get "that sound in your head." Maybe you prefer functional artwork (Ritter).
As far as I know, the only expensive bass that is a rip-off is a Darren Huff bass.
Edit: How many expensive bass bashing threads do we really need?