All releases of GC have these kinds of problems and I really hope the devs will do something serious about it in GC3 because such a single mechanic can totally kill the game or screw with the immersion one gets with it and it just feels not right.... Then again I wonder why the devs don't learn from the same mistakes of the past... (?):
In GC1 one could offer the/all AIs technologies in exchange of money where a single payoff was far less than if charging the bill over a period of 30 or 40 turns. The latter technique allowed the player to sell alot/all techs one by one, and the AI would only stop of buying technologies when he already was hopelessly broke over said number of turns, and thus, didn't pose any threat. With the money extorted one could go on to fund alot of additional research, the techs gained could be used to repeat the same behaviour over and over. Paradoxically the more enemies there were in the game the more stronger this tactic got... tbh this single mechanic killed the game experience for me.
In GC2 (esp. DL and DA, but TOTA also had some nichees) one could practically play the whole game being in debt (hopelessly, without the chance of ever recover from it) albeit still have all planets improvements or ships upgraded to the latest technology (the game will allow you to spend money while being in debt - I put a strategy around it called "the negative balance strategy" which is why, as of now, I am listed #1 MV) but, to be fair, all other top MV gamers would upgrade their ships/hulls at some point to a design yielding maximum MM and that also would make them hopelessly broke (the maintenance cost of this fleet outshone the total income, so subsequently, the debt can only go worse and never be paid back - and this is exactly a situation in which a real bank would never grant a credit of any sort in the first place....)
So please devs of GC3: Make economy a serious business, something you've got to keep a sharp eye on it without any easy out or fast solutions. Preplanning and careful evalution are serious topics of a *strategy* game!