Ok, so now I am dying to understand how this could possibly be the case, as this isn't how the economics are supposed to work... like, according to this calcula

Ok, so now I am dying to understand how this could possibly be the case, as this isn't how the economics are supposed to work... like, according to this calculator, I could make $5 with the old graphics cards in my PC, and I live in California (where I would expect expensive power). Like, the premise is supposed to be that if there is that much profit to be made mining, people will mine, the hash rate will skyrocket, the block production time will get too low, and the hash difficulty will rise until the profit you can make is low enough that you aren't sure if you want to do it anymore. Does the difficultly just not rise fast enough? Or like, is this largely just because the price of Ethereum has gone up "too quickly" in the past month? If so, does this calculator take into account the incentive factor that if people actually do this the difficulty will go up, and so this $7 of profit today might be $0.50 of profit in a month, and maybe you will fail to pay off your hardware investment fast enough? Or is there just something really weird going on in this market that I don't understand (and would love love love to learn about)... maybe it literally is just as simple as "there aren't enough graphics cards to go around, and Nvidia's disinterest in making profit in this way--even temporarily--is the strongest current limit on hashrate"?