From Waterfall to Agile to AI-Assisted
The Linear Era: Waterfall (1970s-1990s)
Waterfall dominated when software was simpler. Requirements → Design → Implementation → Testing → Deployment. Each phase completed before the next began. It worked because:
- Software scope was limited
- Teams were smaller
- Change was expensive
The Breaking Point: Internet boom. Software complexity exploded. Six-month requirement phases became obsolete before implementation started.
The Iterative Revolution: Agile (2000s-2020s)
Agile flipped the script. Two-week sprints. Constant feedback. Embrace change. Key principles:
- Working software over documentation
- Customer collaboration over contracts
- Responding to change over plans
Why It Worked: Matched the pace of business. Developers could adapt quickly. Users saw progress regularly.
The AI Transformation (2023s-Present)
AI assistants changed everything again. A developer + AI can now output what entire teams produced. But traditional methodologies break down:
Waterfall + AI = Chaos: AI needs constant steering. Six-month plans are meaningless when AI can prototype in hours.
Agile + AI = Friction: Sprint planning becomes bottleneck. AI works at near conversation speed, not sprint speed.
Era of Vibe Coding
Vibe coding emerged from developers actually using AI. It’s built on three realizations:
- AI amplifies both good and bad patterns - Structure matters more than ever
- Documentation becomes executable - What you write shapes what AI builds
- Testing is dialogue - Tests become conversations where you show AI what “correct” means through examples
The shift: From managing people to managing intelligence. From writing all code to directing code generation. From preventing bugs to rapidly fixing them.