Everything requires R&D, but doing more things requires more R&D. It’s not just an EV, which requires it’s own R&D.
Custom means it has one purpose, not that it’s a one-off. No one else will be using the same panels they will be, so they don’t benefit from the scale of mass-produced panels (and 10,000 is not a large number even if that’s the number they have pre-ordered).
Everything requires R&D, but doing more things requires more R&D. It’s not just an EV, which requires it’s own R&D.
Custom means it has one purpose, not that it’s a one-off. No one else will be using the same panels they will be, so they don’t benefit from the scale of mass-produced panels (and 10,000 is not a large number even if that’s the number they have pre-ordered).