R&D engineers and car designers are usually separate people from manufacturing and supply chain engineers. Now that Model 3 has been passed onto mass(-ish) pro

R&D engineers and car designers are usually separate people from manufacturing and supply chain engineers. Now that Model 3 has been passed onto mass(-ish) production, Tesla is using those engineers to develop other products. Tesla would lose those talented people if it asked them to just sit and do nothing, or if it asked them to work on areas completely outside their (not just lose, but lose to competitors).