What are you presuming with a "medium-sized" company? Modern financing might very well allow a company big enough to operate only a single factory, to invest in

What are you presuming with a "medium-sized" company? Modern financing might very well allow a company big enough to operate only a single factory, to invest in new technologies, or to purchase them from specialized firms doing innovative research. Similarly, sure a 5-dev team probably couldn't build and operate the full-scope of FB (unlike the clone someone could build in a weekend that doesn't take into account hundreds of small capabilities) - but maybe a 500-dev group could, rather than needing 5000-devs. Especially with a narrower focus on scope and outsourcing various problems (such as do they need to operate their own video hosting platform vs partnering). There are advantages to scale, but also costs, and at a certain point scale tends to be horizontal rather than vertical. More products/features/adjacencies that now need to be coordinated, rather than a solid core and leverging the market for the rest.