In my experience, if programmers always had a complete design specification before starting, and if we always "tore up" the old mess (down to something unquestionably stable) before making any improvements, our software would be much, much better. It'd probably also cost more.
And by the time the software was done, it'd be useless. A house doesn't get obsolete in ten years, but software - which is much more complex than a house - can be obsolete in ten months.
Not to mention that I'd rather not be reinventing the wheel every six months.
I often hear that but it is no true in my experience. Maybe your run-of-the-mill flavour-of-the-month hipster web 2.0 app has a limited shelf life but most enterprise apps stay deployed for years.
But is it because the needs haven't changed a bit, or because it's good enough and it'd cost too much to replace it? Because if software was always tored out, that would only accentuate the latter problem.
And by the time the software was done, it'd be useless. A house doesn't get obsolete in ten years, but software - which is much more complex than a house - can be obsolete in ten months.
Not to mention that I'd rather not be reinventing the wheel every six months.