The old desktop operating system UIs were designed for people who grew up with stereo towers and paper checklists. The metaphors made sense to them. These days

The old desktop operating system UIs were designed for people who grew up with stereo towers and paper checklists. The metaphors made sense to them. These days, people grow up with touch screen devices. Swiping and tapping is the default, not pushing and sliding. There's a reason a checkbox looks like a checkbox: it's a concept taken from the physical world to represent a boolean value. In a world where paper checkboxes are becoming increasingly irrelevant, the metaphor doesn't make sense. The same can be said for square buttons and radio buttons. The "push a single round peg in and the others will pop out" UX from old equipment just isn't around anymore. People who struggle with mobile devices face the exact same problem as the people who struggle with desktops: the metaphors don't overlap so it's hard to predict behaviour.