Exactly. So obviously the code base is an asset. If one then want to define technical debt it is more like the difference of the value of the code base compared to the imagined/perceived value of the code base. But this does not help with anything as well, since you could also just adjust the perceived value of the code base to reduce technical debt.
You cannot reduce the perceived value of the codebase in most cases since the value is already communicated with the customer, there might even be contracts, and SLAs.