Blame the voters of Oklahoma, who voted a long time ago to continue the tolls to create a system tolling regime for the entire Oklahoma Turnpike system.
Unlike the Illinois Tollway, the Pennsylvania Turnpike, the Chesapeake Bay Bridge, and so on, there was an actual vote that approved continuing the tolls.
It’s not just “continuing the tolls” ... it’s the expansion of the road/highway system. In other words the people wanted to expand it. It’s not that they said ... “Oh gee ... why don’t we continue paying tolls and get nothing in return” ... LOL ...