Fair enough, but I think I still would have used the Al wheels. They used known defective wheels, wrecked their project, didn't cross the finish line and potentially upset a big supporter. Not the kind of thing I'd do in a startup, at least.
Look at me though, judging people's decisions on the internet through a second hand story.
Chuck actually recently published a book, documenting his career within CNC machining. He started a company whose product became the gold standard for CNC software for decades.
I imagine it was identified as one of several possible solutions, and the team pursued more than one solution in parallel. As a non-mechanical engineer, I personally would have voted for the aluminum.