I think you might have jumped to the conclusion this company is trying to sell solar cars with unlimited (outside?) range.

No, I jumped to the conclusion that it must be less effective than the alternative of rooftop solar + conventional EV. There is no world in which this is better. Rooftop solar will always have better solar access, and conventional EV will be cheaper because of effeciency of scale. This design is limited to powering the car only, and will never be as ideally situated as rooftop solar. The opportunity cost of this car will be worse than rooftop solar + EV. Sure, for people with unlimited money it might sell, but most of us don't have that and have to compare cost to value and choose the best option for that.