[userbinator]

It's not just planes; I've noticed a lot of things seem to get better over time, then take a nosedive (pun not intended). I wonder if it's an inherent property of systems to do this, or if it's the result of some perverse incentives to have "progress" at all costs.

[pgt]

Yes, it's a type of evolutionary gradient descent: you see an entity get stuck in a locality-constrained hill-climb before it gets culled by another entity that climbed a different hill (of regulation).