You inspired me to do some Googling and arithmetic. From the Apple website, an iPhone is about 0.5 lbs. There have been approximately 1.3 billion iPhones sold.
TL;DR: Cars are heavy. The total mass of the vehicles Tesla has delivered in the past six quarters exceeds the total mass of all the iPhones that Apple has ever sold.
I don't think you need 6 quarters. Using your numbers, 1.3 billion iPhones is 650 million pounds. At 4000lb each, it only takes 163000 model 3s to outweigh the iPhones - about 5 months of production, or two quarters.