Who says you can't upgrade without reinstalling on Ubuntu?

  sudo apt-get install update-manager-core
  sudo do-release-upgrade

It's not impossible, just a horrible experience. Most likely your network drivers will break, their new version of X doesn't support your graphics card/drivers, etc. I have never been able to upgrade Ubuntu without using Ctrl+Alt+F1 a lot. I'm not going to give that to my family.