Because as soon as some percentage of hosts on the internet is IPv6-enabled there will likely be an avalanche effect of people actually taking advantage of it. Chrome and Firefox don't have 100% market-share, yet webapps that push the boundaries of their features are all over the place. We need to get to the tipping point ASAP.
Also, you can ssh to any machine in your home when you are on the road (my most common use case), and this works already.
