I read that apparently if you don't input a password for root that it apparently installs sudo. I might be wrong about this but could be worth a Google
The installer says this when it asks you to type a root password. I don't know why, but for some reason the information is both right there and easy to miss.
The option to not set a root password and instead let the regular user use sudo seems to be mentioned in the installer for the first time around 2007, so it's been there for a while.
Why would anyone continue reading after "you need a password for root"? You just the rest of the paragraph is gonna be ramblings about what constitutes a good password and so on. And it is exactly that and then at the very end they tell you about sudo. No wonder I always missed it.