I have to admit I stayed away from React Native and never understood its real appeal when there were already established and frankly better solutions. When working on web, native or Flutter development I always found 256 GB enough to work with. That's not to say you'll feel comfortable at all times and you'll find yourself cleaning up more, but it's doable. Some really can't afford a new 512 GB machine. There's also the interesting case of the lone software developer who - similar to what you mentioned - has to create the marketing and app store assets as well - who will likely start struggling with anything less than 512 GB or even 1 TB.