I agree this is an amazing strategy when you can do it!
> None is willing to take on the risks associated with technical debt repayment.
What do you think they are afraid of? What risks are there? Is it possible to mitigate these risks in some way?
Sometimes a technical debt repayment may require a big change in business. I saw a banking system where the authorization framework was based on impresonation of users. Repaying the technical debt would mean going over all contracts and adjusting their conditions while developers implemented a more traditional role-based access control.
Such a change was so unrealistic that middle management did not even talk about it until some day the project got outsourced and most developers — reassigned to other projects.
Not OP, but usually there are no (trusted) unit tests.
That is also called modularization.