The Dow Jones doesn’t make sense. It’s price weighted, which doesn’t make sense considering a tiny company with a few expensive shares can have more influence than a massive company with lower priced shares.
The reason is that the Dow was started in 1896, a time when obviously computers didn’t exist. Getting the data and crunching it every night was a huge computing task, so they had to settle for the price since that was quicker to calculate than multiplying out the total market cap.
It’s strange to think that there was a time where the basic task of multiplying a list of numbers was an expensive and time consuming process that required paying a team of people. The assumption that every single person has instant access to a computer capable of processing billions of computations of massive numbers every second is so ingrained into my brain that it’s strange to imagine a time when that didn’t exist.