Wristwatches were supposedly popularized by WWI due to the impracticality of pocket watches on the battlefield.
I believe this is true. Wristwatches did exist before WW1 (they were known as 'Neapolitan watches' at one point because the Queen of Naples had one) but didn't catch on until the trenches made them more useful.
I remember reading that a few years ago and thinking 'it seems strange that people wouldn't just realise how much easier wristwatches are to start with. I mean, it's not like people would ever go back to pocketwatches
now'. AND YET THEY HAVE. Since then, The Youth have started not wearing wristwatches at all in favour of just looking at their phones...which are reasonably-sized bulky objects they carry in their pockets and have to get out to check,
exactly like pocketwatches. Fashion and cultural practice is not something that can be rationally predicted.