The company I work for is still getting quotes of 2+ years on what used to be off the shelf electronic components. When you’re dealing with long lead times it’s really common for the supplier to get the estimate wrong. A couple of extra weeks or months is really common. My gut says the supplier is giving delivery dates and just not delivering. I have been in the middle of this before. You place an order and are told it will be delivered by X day. Which you use to tell your customers when they should expect their orders. The problems occur when you don’t get your parts on time, suddenly your production is backed up and cannot deliver to your customers by the dates you already promised, which just snow balls down the chain.
I do blame Worlds of Fun for not cancelling the opening earlier. I cannot imagine GCI was not communicating to the park about this issue. Likely they were planning to use overnight shipping to get the items as quickly as is possible, and relying on bad information, but they held out hope for way too long.
The impression I have is the parts have always been missing, and that nothing broke, it’s not important to test the ride, and I read where the park was even able to train ride ops. My understanding is that GCI employees have been riding it as well.
All of my guesses deal with locking/unlocking restraints, restraint position sensors, or communication between the train and the station when parked in the station. Something that you can work around or disable without too much hassle but you need working for operating with park guests.