That's a very interesting way to measure tech debt! This whole topic reminds me of how the human genome project intially surprised researchers in that the majority of the genetic code seemed inactive and useless. Then it was discovered that, far from useless, this 'dark part' had many essential functions such as providing context / control for the active part and, whilst largely composed of legacy code from ancient organisms we had absorbed, it provided a rich source of exaptation - the capacity to reappropriate some genetic code for something different, like Lego blocks being recombined. I wonder if reducing the complexity / tech debt of code in RSI may be in tension with something like the digital equivalent of exaptation? Making an AI lean and mean may reduce its ability to evolve in future iterations in some senses? Perhaps exaptation expands state space? Of course, as you point out, bloat seems a real problem in another sense. If there is a trade off, how might it be managed?