Growing up playing video games in the '80s and '90s, I always thought the companies making games were massive. As an adult, I've gone to several retro gaming conventions and seen game creators from back then talk about their experiences. It really surprised me the first time I learned that often those games were often coded by 1 or 2 people. So yeah, those companies behind the ads were tiny by today's standards.
The teams were much smaller than Young me realized as well. The mini interview about the launch of the Nintendo Entertainment System after the video game crash was pretty interesting.