I don't think it's a timing or execution thing. You can have the best engineers and operations on the planet and it still wouldn't work. The benefits of the solar car are just not big enough when compared to a standard electric car.
The problem is that in 5 years they didn’t make it to production. And they needed a bunch of money now, just at end of the EV bubble. They also did an IPO way too early, and in the IPO didn’t raise enough to get to production. These are all timing and execution mistakes, not market match/product issues.