They have to pay a licence fee for every book they include with HeroLab. ie Paizo gets a cut of every sale that Lone Wolf makes. It's another media that you are buying the Pathfinder books in. Also, it takes time and labor to enter/program the content into HeroLab. So they deserve a return on their time. If you don't like it you can buy the authoring module so you can see how much hassle you save by buying the premade supplements.