Between:
* The implementation delays https://www.spokesman.com/stories/2012/jul/19/wsdot-reaches-...
* The payment issues https://www.seattletimes.com/seattle-news/transportation/sta...
* The customer support issues
* the sensor issues (admittedly those may be on the state and not ETC/ETAN, unclear)
and more the state abandoned its contract with ETC in favor of one with ETAN, which took the system offline for two weeks to switch over and admittedly hasn't been much better (https://www.seattletimes.com/seattle-news/transportation/wsd...).
God forbid we let the state hire a few local SWEs (Seattle doesn't have any of those) to write and maintain a system instead of paying $30M every few years plus a cut of tolls to whatever Texas contractor gave the most perks to a WSDOT exec.
There's a good reason that the systems themselves cost so much money. Heck, it costs an arm and a leg just for the routine maintenance permits! The CI/CD, security, data persistence, data provenance, latency, and agency interop requirements are absolutely insane. Trust me, it's more than just a few SWE can handle.
Lastly, it's definitely not about any under-the-table dealings. There's just a huge amount of work! When deciding to whom to award the contract, they do background checks on key company people, look at past contracts, etc.
That's the reality of the situation.
Second, every tolling system is different. Sometimes the accounting (often called the back office system) is contracted out, sometimes it is performed in-house by the tolling agency.
Source: I work for one of the better quality contractors.