If, by your original comment, you meant that if your project is simple enough you can muddle through like this, whereas with a large project you can't, I agree with you. But just because bad design doesn't scale up, does not mean that good design doesn't scale down.

The bottom line is good design is fractal. You absolutely need it to achieve the largest scale, but it pays dividends at any scale. While it's true there are a lot of cases where it doesn't matter, doing so will never make you a master programmer any more than chainsawing a log to make seats around a fire pit will make you a master carpenter.