I was wondering if it would be too much of a hassle for devs to include all three types of drivers for nvidia on install medium. After several years of poking around with PCBSD and now TrueOS, I find it quite unpleasant, to have to install 340 version manually to make my olderish 9800 GT card to work. This problem alone, made my path of understanding how system works, great opportunity to learn many new things. But some dad, trying to re-purpose older machine for his son to try out opensource games might not be that "lucky" (does not have time or motivation). He might go trough the install process, but upon reboot the feel of sluggish response and video teardown will not make them stay on this distro.
Other possible scenario to consider why including all drivers on install medium is a good thing is for situations where you don't have internet access during install, but you need system in workable condition.
I know downside is that so many people will increase download bandwidt on something that has no use for them, but since install medium size dropped significantly since KDE and alike are gone, that driver size is not big issue at all.