Even companies that make the business decision to rely on off-the-shelf software wind up doing some of their own software development to customize things for their environment. And that doesn’t include the stray legacy application or two that needs to be integrated into modern environments.
Then there are companies whose primary business is creating software solutions for clients.
Development projects cover a lot of grounds, from commercial software or internal applications, to client-server or Web-based applications, to new development projects or integrating legacy software, etc. the successful development projects follow the same basic process.