Look at the other side - the op-amp portfolio manager needs new products, new profits so they constantly roll out new op-amps, per the MBA way.
We think cost is driven by silicon area, but I think it's reverse - they have a pricing matrix using features such as offset voltage, speed, RR etc. to determine the pennies to charge and fill some niche left out by competitors.
It's a problem now with the mergers and acquisitions where all of a sudden a corporation now owns previously competing portfolios. What a mess. They have to swing the axe and thin out the lineup. Consolidation (PMI, SSM, Burr Brown, NS, LT) will lead to less competition and poorer offerings because innovation is not really needed. It's ADI vs TI now.
P.S.- on the speed issue, I found
LT1494 0.001V/usec slew rate on super low power 1.5uA, a neat part.