The Daily Grind: How can survival sandboxes keep the challenge fresh?

Shawn and I have had several conversations about the conundrum present in Fallen Earth. Namely, that the first part of the game is really exciting because you get that cool feeling of scrounging for survival and clawing your way out of the wasteland -- but then this turns into a different game when "survival" makes way for "laser tag with high-tech gear in PvP zones."

It's made me wonder how MMOs that are being built with a survival sandbox angle are planning to keep that sense of challenge and building yourself up fresh. I think that there's a point in these games where you have accumulated and built enough to keep yourself comfortable unless the game deliberately removes that attained protection or keeps escalating the danger past the point of lunacy.

So this is our thinking exercise for the day: How can survival sandboxes keep the challenge fresh for players?

Every morning, the Massively bloggers probe the minds of their readers with deep, thought-provoking questions about that most serious of topics: massively online gaming. We crave your opinions, so grab your caffeinated beverage of choice and chime in on today's Daily Grind!