I once ask for the same thing, Eric. I HATE scrapping all my scientific and research facilities when all tech levels are achieved. In later stages of a game, the technology part simply disappears. That's not logic, IMHO.
An idea could be making some features of components or facilities "infinite". I mean, for example, the power of direct-fire weapons. With a technology called "Direct-fire power" with infinite tech levels of dramatically growing cost. The result of achieving each level is a small increase of all your direct-fire weapons power. The cost is important. For example:
Direct-fire power: +Y damage of every DF weapon
Cost(level 1) = X rp.
Cost(level 2) = Cost(level 1)*2 rp.
Cost(level 3) = Cost(level 2)*4 rp.
Cost(level 4) = Cost(level 3)*8 rp.
...
Same could be done with seeker speed, armor resistances, storage capacities, etc. So, scientific research will always be a very important thing, no matter how many time the game Lasts.
It's only an idea
