One person can certainly handle something like this but it all depends on how big the project it. For example, a person who is a good coder and also a designer can run and maintain a simple ecommerce site with fewer modules, features, and products and at the same time if the ecommerce site is huge then it certainly needs more people.
There are many solo bloggers who make big money by sitting dedicated on it and making their career from the same. If the blog becomes big then he/she might need someone to maintain the server, SEO, content, images etc.
Bottom line is it depends on the nature of the website and how big it is, we can decide if it is one person’s job or a team is needed.