systems on boats to be highly reliable.

Firstly, being an engineer, I know all too well that even with the best design studies, it takes some iterative testing to get any complex system running reliably, and this is doubly so with innovative systems.
Boats will never be engineered and tested adequately, because the number produced and the require selling price is inadequate for serious engineering and testing. Cars, refrigerators etc. are MUCH better engineered, partly because the huge market provides sufficient money for excellent engineering and testing.
Aircraft are produced in much smaller numbers, but their selling price allows for excellent engineering and testing

Secondly, crews, particularly those new on board like delivery crews, lack the knowledge of the systems to react rapidly when problems like "stuck on" controls occur. Commercial pilots have extensive training and simulator practice in how to handle such issues.

This has made me think about a few things on our boat. I know how to kill anything dangerous, like a runaway engine stuck in gear, or bow thruster that will not stop. I will make sure the all the crew does in future. We can kill anything electrical with a simple manual breaker on the panel. That covers most issues.
One good reason to have everything properly labelled.

I am starting on installing a new engine next week. This incident has made me decide to keep the manual cable to the helm that will to shut off the engine fuel, instead of relying only on the (new to me) electrical switch.