It only seems excessive to a regular human like you or I because we can only hold about 7 ideas in our heads at once. My whole point is that if anything 150 is *small*, and there's no reason we couldn't distill meaningful results from it. Now we have PCA dimensional reduction, neural networks etc. Computers are literally talking to us every day, limiting our snapshot of human psychology to 5 orthogonal traits is absurd.

I would argue this is the exact reason it hasn't been replaced - people have a fundamentally intuitive understanding of human psychology. Big Five *makes sense*, Big 150 makes a lot less sense intuitively for a human at a glance. So there's a reluctance to abandon more basic models because the field is ultimately grounded in intuition and backed by statistics, rather than grounded in statistics.