You're completely right about the psychological resistance. I don't know why but even hard core tech people take time to get over the addresses and I think this has been a major factor in the lack of widespread adoption.
You're completely wrong about the number of IPv6 websites. There are thousands available and the growth has been noticeably accelerating since the 2008 Google IPv6 implementors conference. Every year around conference time more major sites announce availability. This year Facebook was the big one (but not the only one!) to announce a beta site.
Also - try running a torrent on a dual stack connection and you'll clearly see that IPv6 is very popular among torrent users.
There are a couple of major things coming up that are really going to impact this whole IPv6 discussion in the next couple of years.
There has been ongoing work to make IPv6 -> IPv4 NAT work well. This will be needed for sites that can get an IPv6 block for free while an IPv4 block is expensive or unavailable. See here - http://ecdysis.viagenie.ca/
This NAT64/DNS64 technique is available today and makes an IPv6 only connection 95% usable for IPv4 sites and 100% usable for IPv6 content. The IPv4 breakage is sites that hard code IPv4 addresses directly into HTML or XML, or whatnot which is easily fixable if there is incentive. Now for some incentive.
T-Mobile has decided that NAT64 is the way to go so they intend to start rolling out IPv6 only phones using NAT64/DNS64 to get to IPv4 sites. This means that in the next couple of years there will be a couple million handsets that are IPv6 only accessing the IPv4 through a large scale NAT64. Verizon is joining the party using dual stack IPv4 NAT/IPv6 native phones. Think about the _global_ demand for cell phones and you can see what will be driving IPv6 adoption pretty clearly. It dwarfs the PC market so the old way of thinking about your aunt's Linksys don't really apply. Mobile web is rapidly increasing in importance and you won't have to do anything more than get a new phone in a couple of years to join the IPv6 party.
Comcast, AT&T, and others have announced IPv6 trials in 2010 and 2011 respectively. These could be production systems a year or two down the road. When that happens, anybody who is running Mac OS X, Vista or Win7, or Linux is likely to automagically get a working native IPv6 connection very quickly after that when they or their ISP replaces their home router if it wasn't already v6 (Apple, Buffalo, or recent D-link). This is going to largely coincide with the IPv4 free pool exhausting itself which will give another kick in the pants to adoption.
You don't have to spend a ton of money - all the pieces have been in place for some time in most networks.
It's true that businesses would have to spend money if they wanted to completely eliminate IPv4 but there isn't actually a need to do that. At many companies - most or all of their web facing presence equipment has likely been IPv6 capable for a couple of years now. What's needed is to get a connection (tunneled at first and then native when the traffic demands it) and turn it on. You don't have to eliminate IPv4 internally and you don't have to switchover everything. It's a transition and we don't need to make a false choice when neither the situation nor the economics demands it.
Sorry - got off on a rant there.... :-)