It is quite easy to hit the end of the tech tree. In some PBW games where there is a huge (255 system) map, the tech tree can often be nearly finished (with only useless techs to go) by turn 130 or so by several players (or more). Try playing mods with extended tech trees. Proportions is extended, as it costs more to research stuff. Adamant is extended, but still in alpha Version. You can get the Junkyard Mod by Puke and then add the research centers back into the mod, and it gives more levels to a lot of tech areas. There are many other mods with longer tech trees out there.
