Very true too...the reason I ask is becuase I was thinking the other day. As you get higher up and the Bills get higher, and your income gets bigger you can cover the costs of improvement swapping. But younger Nations, when they try to say swap LCs or GCs to reduce some bills for Banks/Stadiums, etc. the costs of those improvements may pretty much eliminate what savings you would've gotten.
At some point though (that right Infra level where your Citizen count/Income, Trades, etc.), will all start turning a profit in the improvement swaps, with the costs being covered, and your Nation at the very least/worst: breaking even.
I hope all of that made sense...