The cost of rewrite at that point is typically less than cost of straightjacketing the existing codebase to support all new requirements, otherwise it is less l

The cost of rewrite at that point is typically less than cost of straightjacketing the existing codebase to support all new requirements, otherwise it is less likely to happen. So, defaulting it is. (Mind you I'm not fully sold myself that 'technical debt' is a useful analogy at all)