Shutting down manned tool booths is something we've been seeing more and more across the country. For example, when portions of SH-45/SH-130 opened bypassing Austin, the manned booths were closed within the first year and to date, some of the booths have never been manned (they were already built when the decision was made to automate). The reasoning behind this, it wasn't financially viable to man the booths when some 70% of the vehicles using the road were either NTTA tagged, TxTag tagged, or EZ-Pass tagged which brought about a interoperability act between the toll authorities to accept one another's tags.
Long story short, with more and more vehicles having some kind of toll tag and interoperability agreements, even with other states (i.e. many of the toll roads in OK will bill my NTTA account instead of making me stop or read my plates), and the cost of labor skyrocketing due to inflation it's just not financially feasible to continue to staff toll booths. It's not just an Oklahoma thing...something that is being seen all over the country.