Because it is a status symbol. Back in the day, nerds wore calculator/remote control IR watches to show they were true nerds. Now, nerds don't wear watches, because they have clocks on each of their 20 electronic devices they carry with them/use every day...
Rich people and Rollex have a strong history. But some people like less gaudy watches, that still have some real world practical value. Omega fills this on the high end, where Seiko is a bit lower down, and more consumer grade is the Invicta watches...
There are more of course, and their prices usually have to do with their uniqueness and material value. But watches are to men as jewelery is to women...