Totally agree, Flutter app development cost (https://www.nimbleappgenie.com/blogs/flutter-app-development-cost/) is often misunderstood because people focus only on UI and ignore everything happening behind the scenes. In my experience, long-term maintenance and scaling are the most underestimated factors, especially when user growth starts impacting performance and infrastructure. Backend complexity and proper QA also add up quickly, but it’s the ongoing updates, bug fixes, and optimization that really shape the true cost over time.