I had always understood the "Lifetime 3G" to mean that it would always be available for me to download books, magazines, etc to my Kindle at no charge. Unlike the sending of documents, which is free for WiFi but there is a small fee to have them sent 3G.
As for the browser, I love it, hope to always have it, but I also realize that it could be pulled at any time. I figured that's why they put it under "experimental" so that if they decided to discontinue it, the Kindle Store, being separate, wouldn't be affected.
I don't think Amazon "owes" me free 3G to surf the web however primitive the browser is
but I'll enjoy it while I've got it.
Bergette