What baffles me is people having the stock macOS apps in the Dock without taking the time to at least remove what they don't use. I think this goes to show that for most people they don't even notice the Dock is there.

Yes drives me mad.

Maybe they don’t realise you can change what’s there?

Vast majority of computer users (including phones) don’t customize anything beyond the out of the box set up. In fact, I’d that’s even true for my sass customers, only particular percentage of them use any of the customizable settings. Which is why UX is so hard, we have to do our best to make sensible default choices. As technologists, it’s very easy to forget this while on the thick of it.