IMHO prestige is better linked to Wonder achievement, because:
a) the tech race is a common state on balanced Civ
b) winning any tech race is an advantage by itself.
c) I can't remember of real "prestige" effect of any development, if not by side effects: better weapons=less likely to be attacked, better resources=more trade income and more production, better production=better city development, better research=better ...
Ok, you get it
We are in search of a way to keep the game balanced (i mean open to any winner) as long as possible, where too much advantage for a tech winner will quickly "opens the scissor" between nations too much.
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Admiral Naismith AKA mcostant