The first sentence from the wikipedia article seems good to me: "R-seeking is the act of growing one's existing wealth by manipulating public policy or economic conditions without creating new wealth."
"Rent-seeking middlemen: These actors insert themselves into a transaction by force, law, or monopoly control. They do not make the trade easier or better. They just demand a toll or fee because they control access."
Monopoly app store enforced on devices by firmware/operating system lockout inserting yourself as the only middleman to distribute things meets the definition.
google "economics rent seeking app store"