Alternate Tech Trees

Yesterday I commented on this G+ thread, where we were thinking about durability. Should a mature spacefaring culture build for permanence or recyclability? Both? Would they leave permanent artifacts on planets they've visited or would they follow the Prime Directive and make sure anything they use would decay quickly to keep from influencing indigenous life?

And it got me to thinking about technology, since you can follow the quick energy, fossil fuel using consumer culture, or a more harmonious culture of constant reuse, or even a more oddball basis like a living biological entity as the basis for technology instead of inert elements dug out of the ground. Changing from one approach to another one causes some interesting conflicts, like Mad Max or a Dystopian Steampunk setting. But what if we change the base assumptions instead?

I love Sid Meier's Civilization, but here's my problem: it assumes we're on the only viable path for technological development. Even the mods to the tech tree in the various hacks don't allow you to stretch beyond the structure of pottery-equivalent tech must come before masonry-equivalent tech. What happens when there's no societal need for building walls? If your entire race can fly, walls don't serve any useful purpose and seem downright silly. I'll digress in a different post about the fallacy of traditional castle design in a world where you can make people fly incredibly cheaply.

Technology is all about solving problems at a societal and personal level. The first issues humanity faced were really big: How can we all survive lean times when we can't get enough food from our environment? Our solutions to that problem were many: granaries to store food from year to year, farming techniques for better resource planning, and domesticated animals to bring food with us as we wandered the earth. But what happens when we change those answers? How do we envision a society whose fundamental technologies are so different that humanity evolves differently and advances through modernity on a completely alien vector?

The one approach I can see is to compile a list of cultural problems and think about different answers. The most basic problems involve getting enough food to free up members of the tribe to do something other than gather food all day. We went down the cultivation and domestication path, but would it be possible to stay hunters and gather enough surplus to allow for a class of scientists and inventors? What if we went a completely different path and someone provided a replicator that created food out of thin air? What would that do to the society? Would everyone focus on pursuits other than food gathering? Would everyone live a Logan's Run-esque life of leisure? Or would people effectively be enslaved by the people controlling the replicators?

Which solution to what societal issue would you like to change? I'm just musing out loud here, but if you've done any thinking in this area I'd welcome your input.