From what I’ve seen while following different product teams, launch is usually just one milestone rather than the end of the process. After the app goes live, developers often monitor performance, fix small issues that appear in real usage, and release updates to improve stability or add new features. There’s also a lot of work related to user feedback, analytics, and scaling the app if the number of users starts growing.
I recently came across a detailed explanation of how the mobile app development process continues even after release, which breaks down the stages before and after launch quite clearly: https://weelorum.com/blog/mobile-app-development-process-full-overview-based-on-strong-expertise/. It explains that maintenance, optimization, and regular updates are a natural part of the lifecycle. In practice, many successful apps evolve gradually over time rather than staying exactly the same as they were on the first day of release.