The resistors are manufactured so that they are "guaranteed by manufacturing" such that the outliers are 1%, 5%, 10%, etc. And they do statistical checks on batches, but not really looking for the 10% outlier (which is stupendously rare and very difficult to catch) but looking for slight drifts off nominal (which are much easier to spot) which would result in more outliers than expected.
As such, if you measure resistors, you tend to find that you get really close to nominal--much closer than you would expect for 10%, say. Resistors are so cheap that binning simply doesn't make economic sense.