It sucks that so many people turn these threads into something the initial poster wasn't wanting, and specifically asked to keep out of the thread. Fortunately, most of the posting has been constructive thusfar, and I don't believe 'letting the thread die because the subject has been covered' is really how talkbass operates or stays interesting. The simple truth is that the high end bass market is constantly changing, so I enjoy reading these threads and seeing how they change over the years.
To answer the questions put forth- Its a combination of many of the answers already suggested here, and its going to be different for everyone who's buying a bass at this price point. Some want an instrument made by someone special or a logo, some want a combination of attributes only available from specific builders, some want bragging rights, some want an instrument that speaks to them, and some want to just support an artist/luthier/business that they think is worth supporting. For me its been a combination of the above as well. I wanted an instrument with a super long scale, custom pickup, custom electronics, 6 strings, made by someone who's an influence on me who owns a business I'm happy to support. He makes 30-40 instruments year, lets say on average $5000 each- lets say that's $200000/year gross. Take in to consideration 2 workers, a shop in Brooklyn, materials, machinery/tools, and its pretty easy to see why at 75, he's still working 10hour days. No ones getting rich in that shop, but there are some cool people making some cool instruments and I'm happy to be a part of that. Now that i have the instrument, yes, I post pictures about it online. People are curious about it and I'm happy to share it with others- is that bragging? I've gotten countless PMs asking about it, so why not share. And to those who would prefer to keep their information to themselves, that's their instrument and they can do what they please.
As many have said before- the price is dictated by the materials, work involved, and demand. The most expensive instruments have the biggest combination of these 3 things. Pickups and electronics might seem inexpensive off the shelf, but lets not forget that many of these caliber of basses come with custom wound pickups, out of better materials, which means more labor and more initial cost to the builder. Things like custom strings, better cases, and offering all kinds of options all add to the initial investment by the builder and the prices of instruments will follow.
As for my experience, I have a 6 string 38" scale bass made with a variety of top quality hard woods, custom extras like a wooden bridge, nut, pickup cover, strap buttons, knobs, truss cover, tuners, and switch tips, a pickup wound from silver, custom hand made capacitors, top quality pots and wiring, as made by someone I want to support. To someone who sees a bass as a tool- this won't make sense, but I see my bass as art, and it inspires me to make music I wouldn't otherwise.