Oh, you've hit a pet peeve of mine. I am working at a company that had revenues of roughly $65 million dollars last year. We have grown revenue an average of 72% year on year for the past 7 years. We are looking at a 125% increase in revenue this year, assuming that one third of the projected contracts are actually signed. It could be as high as 200%. This means that 7 years ago, we had revenues of 1.5 million dollars. In 8 years, we have increased 100x. Our IT staff has gone from 2 people to 22 people. Our total staff has gone from 20 to 250.

What does this have to do with anything, you might ask. It's very simple - our systems have grown incrementally with an extremely short feedback loop. And, they are best described as cancers or weeds. The system is a mess and it is more dangerous to modify it than it is to throw out and start over from scratch. Except, refactoring now would cost $500,000 and take a year. Ooops!

Remember - incremental design does not in any way imply successful design. In fact, it almost never does. You end up traversing the twisty maze of:

• Poor requirements (assuming you even got any)
• Inadequate development time (assuming you even got a fixed deadline)
• Zero testing (TIP/DIP, anyone?)
• Inappropriate executive-level decisions
• The wrong people in the wrong positions
• Complete lack of experience in fundamental roles

You are right - a hallmark of most successful modern applications, proprietary software aside, tends to be incremental development. It is a necessary condition, but it most certainly is not a sufficient condition. There are at least three other conditions I can think of that are required that incremental development doesn't even begin to touch.

• Clear and concise development process which includes peer review at every stage and a strong focus on repeatable testing
• Clear and concise requirements
• Experienced management that understands the division between their roles and the roles of their staff

Give me a project with those three conditions and I'll be happy to work top-down. Give me a project whose only bright point is incremental development and I'll quit in less than 3 months.

Another personal story - I worked at an e-commerce firm which had a continuously incremental development cycle.

• We'd release on Sunday night.
• Monday, we'd receive requirements.
• We would have 27 days to complete development on those requirements.
• We released four weeks from the prior release.

Yet, we had no test suites, no design, no peer review ... no nothing. When I asked about design, my director said "Do it on your own time." But, we had incremental development, so we should've been ok, right?