I do think the perils of dirty code are often overlooked, especially by management who want a 'quick fix' and feel code quality is vanity.
The primary problem with dirty code is that it adds a cognitive tax to the code base - anybody coming to the code base is going to have to invest considerably more effort attempting to unravel the mess than the problem at hand actually demands.
The more dirty code grows, the worse it gets, sometimes to the extent that the code base becomes so messy that certain features become prohibitively costly, and the road back is long and arduous.
Maintaining clean code (which basically implies constant refactoring) is a lot like brushing your teeth - seems like a hassle at the time, but if you don't do it you're pretty well irreversibly fucked in the long term.
The primary problem with dirty code is that it adds a cognitive tax to the code base - anybody coming to the code base is going to have to invest considerably more effort attempting to unravel the mess than the problem at hand actually demands.
The more dirty code grows, the worse it gets, sometimes to the extent that the code base becomes so messy that certain features become prohibitively costly, and the road back is long and arduous.
Maintaining clean code (which basically implies constant refactoring) is a lot like brushing your teeth - seems like a hassle at the time, but if you don't do it you're pretty well irreversibly fucked in the long term.
Also on this subject - the 'Big Ball of Mud' architecture [anti-]pattern - http://www.laputan.org/mud/