The reason why you bundle installers like this is to catch the 'press yes to everything' group of users. In this case it's done for the greater good (mostly), m

The reason why you bundle installers like this is to catch the 'press yes to everything' group of users. In this case it's done for the greater good (mostly), most users don't care about security updates or upgrading outdated software - a bit like hiding medicine in your food, they won't eat it if they know it's there. If you had it at the end you'll get very low participation rates. If you're installing DirectX it's because you are trying to play a game, so an additional screen to the effect of 'would you like to play your game now or in 5 minutes' will result in everyone picking the 'play game now' option and nothing being installed.