Modern materials and engine designs result in very little debris getting into crank case, so a large filter is NOT needed. Back in the days of open crank case vent tubes, valve cover vents and breathers, and crappy air filters, quite a bit of dirt could get in. As well as lots of metal particles from engine wear.

A filter 1/10th this size would probably still be adequate...

Unless you drive only on dirt roads and use K&N air filter and only change oil filter every 50K miles. In that case, you may need bigger.