Here's the answer you'll get if you write to their support complaining about the change: Hi Obie, As often happens in the software business, vendors “end of life” older platforms and migrate customers to new versions or platforms. The service you purchased a “lifetime subscription” to will no longer be supported or available from Joyent. On the other hand, we appreciate and value your business as an early customer. A…
That's the boilerplate that the support desk is sending out to everyone. I suppose the question to ask is this: "Were you lying back in 2006 when you said the offer was good '[a]s long as we exist', or are you lying now? Or did you decide to renege on your promise somewhere in-between?" You'll get the same boilerplate response, but it'll be on record.
This morning I found this Jason Hoffman post about the EOL and a possible refund here and added to my response email: http://discuss.joyent.com/viewtopic.php?pid=240955#p240955
In my case and theirs, I consider this partial refund ok because I have been using his service 8 years and now I will move my small sites to a cheaper host.