What makes an expensive speaker expensive

Lots of good information and analysis above.  One thing not mentioned is what are the actual street prices of the $$$ speakers?  Leaving aside "industry accommodation" pricing, what do real consumers actually pay for a $50K or $100K speaker?  I have no idea and I imagine it varies widely, but it would be interesting to know what the average discount is on these uber high-end products.  The only speaker I bought new in the last 20 years was obtained at a very substantial discount from list.  It was not in this price category but still, it didn't take any arm-twisting on my part. 

Of course, the most basic answer to the OP's question is:  "Price".

Marty, not sure why the 2k ones do it for you over the 10k ones.  Maybe there is something major missing in the more expensive three you have or you have the smaller system in an area where you listen more often.  Personally, I've owned and still do a few different systems in different rooms in my house.  Whenever I can listen to my major system with the Vandy Treo's, I"m all in.  It's the one that I connect with and love to listen to for hours and hours.  That's just me.

When I say reverse snobbery, it really is when folks make blanket statements that spending over X amount isn't worth it or it's  a waste etc..  The bottom line is that if folks want to spend that and feel that it is worth it, then it is if they can afford it.  I can't afford speakers over 15k and even then it's a STRETCH.  That doesn't mean that I feel anything over that is a waste.  My favorite speakers I've ever heard in a system are the Vandersteen 7 mk2's.  I've heard a lot of the 100k plus speakers set up the way the dealer or manufacturer wanted them set up.  They just haven't done it for me, but there are thousands who love them or they wouldn't be produced.  Conversely, it is snobbery when someone says you can't get great sound unless you spend X amount.  I fell in love with a system that consisted of a Rotel integrated amp with a Vandersteen 2 that was set up properly.  It was running with an Ayre Codex DAC/headphone amp.  

I'm also into personal audio and have a few pair of IEM's as well as headphones.  They all give me different things and are easy to collect.   I can say that in personal audio, you can get dynamic and wonderfully sounding music for very little if you want to.  You can also get unbelievable sound if you want to spend more money just like in speakers.  I do feel snobbery goes both ways just like it can in anything else.  That's not a negative as we are just passionate folks (as long as we are still respectful.  I try to be, but probably don't always succeed).