Depends where you live, in extremely dusty places or lots of pollen places color doesnt matter, all colors will look like garbage after a week. I currently have a black, white and silver cars. This time of year (spring) the pollen looks terrible on all of them (because its yellow).
Rest of the year however, since we dont get rain April - December, even black only needs a wash every 2 months or so.
But on MY, that black trim and black plastic on the back, and black glass that covers half the car will show dust/pollen etc... so I dont know how much extra time you can really squeeze out between washes. Plenty of black on Teslas, even white ones. Sure your white paint will look good, but then the tinted glass and roof and plastic trim all around, and wheels and big ass black plastic piece in the back will show all the dirt.