And unlike a sports stadium, this is for a business that actually *makes* things and regularly employs large numbers of people. It's not just going to be a bunch of tourists and rocket fans rushing in for launch for a few hours, buying food and rocket hats from the launch facility, then going home.
First off they're going to be needing a permanent staff for operations, including locals for things like maintenance, cleaning, phone services, construction, and similar jobs that don't make sense to bring a specific person for (the actual operations people will likely not be locals, unless Boca Chica has an unusually high population of world-class physicists and engineers). All those people will now need places to buy food and clothing regularly. They'll need houses or apartments and the associated services and utilities since they will be permanent residents of the area, unlike the visitors to a stadium. They'll want restaurants, entertainment, shopping centers, bars, and so on.
Then there's the side expansion involved in something with an business like this moving in. If this becomes the primary commercial spaceport, then you'll probably see businesses dedicated to building satellites and similar stuff spring up nearby. SpaceX and other companies looking to launch will likely consider creating a sizable assembly area, to cut down on the risky and expensive shipping of giant-ass rockets. There will also likely be call for purely commercial offices to be set up for the companies contracting with SpaceX, to represent their companies locally and maintain their own operations related to their corporate satellites.