[almostdeadguy]

There's (at least) three causes of technical debt that aren't due to engineering negligence (but I agree in general that many sources of "technical debt" are self-inflicted):

1. Domain modeling shifts. Engineers get a sample of the business rules for the domain they're trying to model every time they build a feature, but it's an incomplete picture. And in fact sometimes the very nature of what the business is trying to accomplish changes. That can require fundamental shifts in how the problem is modeled.

2. Changes of scale. What was engineered to support 10,000 MAU will not necessarily tolerate 100M MAU. Scale can be insidious for tech debt because it's often a slower creep of a problem w/ a high cliff in the amount of effort required to solve for it.

3. Planning/communication failures. Sometimes a critical aspect of a feature is not fully understood or articulated. Or an important delivery date for a promise is overlooked. Depending on the nature of the company's business, an early stage company often doesn't have a choice but to deliver on things that weren't properly scheduled.