Depends on team size. With larger team the technical debt turned into a positive feedback loop. Not good. Cyclomatic complexity increased. Methods became a black box. A junior coder would copy and paste a method and change one parameter to make it work for a new context. Nearly identical methods would proliferate. Milestones would slip.

Here's how I dealt with each:

1) reduced the internal team to half its size

2) fired the offshore team and started from scratch

3) personally attempted a mass refactor / 90 hour weeks

4) refactored 49K line C++/ObjC++ to 29K Swift

Result of each:

1) product shipped, became industry standard

2) Speed improved, Apple offered to feature product

3) I failed, resigned after burnout

4) Easy and enjoyable refactoring to SwiftUI