Donald Draper wrote:
It always amazes me how a significant segment of fandom expects a huge level of consistency in details. Visual details, facts, etc. They notice the perceived inconsistencies in new productions. Which shows they have an eye or ear for details. But if that is true, why are they so dismissive or ignoring of older inconsistencies?
Because that's the way the human mind works. Over time, as we review our memories over and over, they're subtly rewritten every time we think of them, and they merge together into a fairly uniform model of how we perceive the past. The brain is adapted to extrapolate patterns from data, and to an extent that includes ignoring data that don't fit the patterns we're building. So over time we create a unified view of the fictional canon that glosses over the inconsistencies. But when a new installment comes along, we notice the inconsistencies more because they're more immediate, and because we haven't yet had time to rationalize them into our overall construct of the canon as we have with older inconsistencies.
It's the same neurological mechanism that produces the nostalgia illusion, the false perception that the past was better than the present. Our memories gloss over the bad things, the cognitive dissonances, the speed bumps, and smooth out the past into a constructed narrative of what we believe it to have been. But in the present, the things that don't work or don't fit are right there in front of us so they stand out more.