A very exciting, and very unproven company. So B- (or a few notches either way) makes sense enough.
Don't underestimate "lust".
Apple didn't get as big as it is by making a low end consumer product, it has consistently priced itself at the top of the range, which it can justify with it's renowned ease of use and "it factor".
Apply was once a B- rated company, before the iPod...
Times are changing. Tesla looks to be the first new US auto-mobile manufacturer for decades that actually has a chance of success long term.