If they'd update the "value" of every token ever created, they'd need a dedicated staff just for this purpose. It's also not that easy. You need to figure out for each coin what value you attribute to it. Which exchanges are they traded on, how are these exchanges weighted? What happens if the price difference between exchanges is too high? What if the price surges (or plummets) on one exchange and so on. There is a reason why not all coins are listed on coinmarketcap, worldcoinindex or equivalent sites.