TLDR; The author argues that you want to aggregate the demand side and offload actual production, inventory and even logistic to someone else. The example is Kylie Jenner who runs billion dollar cosmetic business through 5 employees and only handles brand/marketing while offloading everything else to others.

This is similar in advice from various life coaches like Tim Ferris et al. The problem with this model is that your supplier eventually will take over your marketing with parallel product and leave you in dust. Margins in business are like vacuum and people will eventually move in to reduce them.