They discontinued white exactly when the autopilot 2 hardware was introduced. They'd had an incident before with the autopilot having difficulty distinguishing the background sky from a large white object. White is a popular color so I figured there might be a problem with the cameras and the bright white. Maybe both that silver and the white went for the same reason.
I like white, all our cars are white, and I'd have ordered white even if priced as a premium color. It stays cool to the touch in the summer, it is always one of the most popular colors, and I believe it is safest with a white car being most easily seen.
When they discontinued white I emailed Tesla to see if it was permanently gone or would it be back. I got a reply that the'd deleted it in order to make my ordering decisions less complex. From this, One would gather I'm thought capable of interacting with most complex automobile software environment available but the one time color choices were just a wee bit too complex for me. This seems unlikely so I wrote that explanation off as spin.
Choice 1 is that perhaps they eliminated a real problem at exactly the time they introduced the new camera setup. Choice 2 is that Tesla recognized a bit of complexity in their ordering system so decided to make things simpler by eliminating one of the colors people selected most.
Choice 3 is that they want people to spend money for a premium paint color instead of a base color to increase revenue.
Choice 4 is what someone else suggested, that they might be reserving white to later identify self driving fleet cars.
Choice 5 is that Tesla has developed some sort of new problem painting their cars white (or silver).
I'm thinking choice 1 is probably more likely than most of the others. I'd like to think they don't really consider us the color confused simpletons that their official email suggests.