Heckin insightful, and I'd hazard that there's going to be (at least two) types of LLM-content-infused tech-debt piles, both of which are essentially job security for anyone who can avoid making those sorts of...conglomerate monoliths.
--> The first kind will be more common, but easier to fix, and is the result of developers using an LLM (or perhaps many developers using a series of increasingly deranged LLMs...) to refactor an existing, mostly-human codebase.
--> The second kind is LLM-generated from the design to the code, and will be numerous at the "hobbiest vibe-coder with an app or ten on various platforms, all with varying levels of security hardening and actual functionality" level, but far less common at the "pays for professional-grade maintenance" level, but then more common over time as the previously mentioned kind get...bought out and professionally remediated by the megacorp that consumed them...or wrecked and re-implemented somewhat Corporate-ly...by said "Business transition" type project, as mentioned. Sheer volume of these will produce the occasional long-running tech pile, with extremely subtle (or glaringly obvious and...tolerated) defects that generate most of the frustration and burnout in their organizations and userbases.
For the projects that use reasonable engineering guardrails, it'll become a tradeoff. Handcrafting every line of code won't be necessary, but there will always be a cost of unverified code. That fact regarding unverified code hasn't changed because massive data theft has enabled statistically-tailored acceleration of the "look up solution, implement tailored-to-my-project conglomeration of a solution, validate, look up solution..." loop, at least until the so-called "AI" models move beyond just the voicebox component of layered intelligence. Design has to come first. Unstructured projects become a cancer of sorts, unshapen and restless, sapping the life from their users.
Do you remember when we were operators of equipment, rather than "users" of "product"?
Pepperidge Farm remembers.