I live in northern Germany less than 250 miles away from the origin of the Dutch bike. A Dutch bike was my first thought when I wanted to try something more comfortable. I tried it for a while and yes, they are comfortable like nothing else but as you said, they also top out at lower speeds. My commute is 18km (11 miles). I don't have the time or energy to push a dutch bike 22 miles every day.

Dutch bikes are awesome for Dutch conditions. Perfectly paved and perfectly flat bike paths, no curbs, only few lights (consistent driving speeds) and the occasional cobblestone. We don't have those kind of conditions here.

What I have are country roads, potholes, different gradients, badly maintained bike paths in the city and strong head winds.

That's a great idea. I hadn't thought of that. I'll try that as soon as I can get my hands on cheap aero bars.