Ironically OP has answered his own question. CS is user hostile. There's far too much interest in tech for its own sake than in designing humane experiences. I

Ironically OP has answered his own question. CS is user hostile. There's far too much interest in tech for its own sake than in designing humane experiences. In fact most commercial apps - banks, flight bookers, and so on - are usable. Not superb, not outstanding, but certainly good enough for the job. But the user friction comes from dark patterns and weird decisions. Example: we booked a hotel on booking.com recently and there's an option to pick a double bed or two singles. Turns out that whatever option you choose the hotel gets a message that says "This booking needs a double or a twin room" and doesn't specify which. There's probably a good reason for this bizarre and unreliable behaviours, but I have no idea what it might be. The unreliability happens in the giant apps. Chrome had a problem with Streetview recently, and then it had a problem opening PDFs. OS updates are notorious across all platforms. But these are huge, frankenstein projects with significant hardware dependencies. Even if you modularise them, formalise them, and test them, how are you going to do that for every possible feature on every possible hardware combination?