Thinking of Congress as a single entity that is capable of sustained memories is dangerous. Congress is a hive of bees, half of whom absolutely hate the other half, with individuals' life spans being potentially very short due to the mandatory fight-to-the-death that happens every 2 or 6 years. Said deathmatch inevitably leads to significant distraction, as well, since any sane individual is going to be concerned with their own survival to the point of preoccupation if it's constantly under threat. So each of these individuals is operating in the service of their own interests, which may or may not be in line with the interests of Congress or the nation as a whole.

Individual congresspeople might see why a past decision did or did not work out well in the long run. That's very different from seeing whether the same decision is politically expedient in the present moment. Nor does it necessarily imply that Congress as a whole is even capable of forming stable memories that can reliably retain that sort of knowledge.