With weekends, public holidays and vacation days I work 220 days a year and with 8 hours a day that’s probably not far off the total hours of the 150 work day medieval peasant

A dedicated e-reader is way better for reading than a smartphone or tablet. They use e-ink screens which are better for your eyes and for battery life.

Also there are dedicated mobile music players. A lot of them are targeted at the audiophile market and can drive high impedance headphones and have a high quality dac. But most people aren’t audiophiles and don’t use headphones that would benefit from something better than a smartphone.