first off, I think scaling in general is a good idea, just the way to implement it and under what conditions needs to be discussed. personally, I would be hesitant to cut rates by half if the available ressources would be halfed, but I guess that is something that would need to be actually tested for fun.
another aspect that I say in this thread was the idea of forcing choice upon players. I have two examples - although not specifically with tech - how a choice is presented to players.
a) the hard choice as in Heroes of might and magic IV where the player had to choose between two possible units to build.

the soft choice, where - for an effective gameplay - a certain specialisatio is necessary. this I encountered a lot in rpgs and its personally the type I favour. it should be balanced in a way that it is possible and necessary to have a good combination of forces, maybe one that even builds on each others' strenghts, but requoires a selection of abilities - or in this case technolgies - to really select in order to be successful. now, what could this be? maybe if you research armor for frigates, then weapons and thrusters tend to be cheaper ressources which would in turn lead to someone having a force composed of relatively more (beware more not only) frigates than someone would have who did the same specialistion on cap ships.
in that example though the specific class should never be so strong as to kill its own counter. otherwise its just a way of training a uber unit (of course a good player would see the others' specialisation and upgrade the counters accordingly, so this sould not be so much of a great danger).
on a side note: is there any way of getting techwise espionage? like what techs the enemy has and what he is researching? would be interesting to evaluate what kind of counter attack he would technically be able to mount.