How large of a sales team does SpaceX have (or need)? How about SpaceX's privacy compliance and data governance? Red team to try to see how a feature could be used nefariously? Internationalization of the content? Moderation and content teams to make sure that the sales or marketing doesn't have to answer awkward questions about why advertisements are showing up in disreputable parts of the site?

Yes, Twitter doesn't build physical things or operate any store fronts... but that doesn't mean that there isn't a lot of complexity that is within the company and the way that it maintains its funding.