[roc]

Only because "air drying" is a more acceptable option than "not washing". So a combined station would only slow things down inasmuch as people no longer skip drying.

In general (at least in the US) drying takes far longer than washing. Because most people wash quickly/poorly whereas driers are on timers and most are horrible.

And when your hands are still wet even after negotiating the unresponsive sensor and waiting an entire drying duration, it's understandable that many people would just as soon skip it.