Genuine question: where do you live where biking 20km to get to work is a norm?

Rural areas in the east of the Netherlands. My cousins were about ~25km ride from high school, I was much closer at 6 or 7km.

Over two hours of biking in rain every day sounds like quite a lot to be honest. And I definitely would not want my kid to drive 40km a day in snow or on icy road. Even if split into two 20km segments.

I had 10km from home to university. I would definitely not want to do double that amount everyday. Even as I was in shape at the time, doing it on bike everyday would be severely unappealing. It would probably also meant that biking has to be the only sport I do.

Biking isn't a sport. That's the root of the normality of the above situation.

Biking 40km a day does amount to sport. Walking is not sport either, but hiking 8 hours a day amount to one too.

If nothing else, both take huge amount of time. If you go those 40km slowly (or environment prevents it), you are looking at very long commute. If you go them fast, then you cant claim it is not a sport.

Maybe, but you'll find that the first thing that needs to go if you're serious about bike-centred commuting is the idea that it is a sport. It's not, just like how commuting by car isn't a rally.

It’s common in Europe to use the word “sport” as Americans would use the word “exercise”.