Software has no physical collapse threshold. Bad code can keep working while accumulating more indirection, worse performance, and higher human cost; the business dies long before the code hits a floor. Even “technical debt” is too optimistic a metaphor, because financial debt at least has bankruptcy.
This explains why quality does not self-correct. There is no day when the codebase topples, only the steady conversion of product margin into headcount, cycle time, and fear. If no natural constraint exists, the team has to build one.