The argument on technical debt isn't wrong, but it doesn't fully take into account the importance of this information and the legal requirements these agencies are held to. Just because it's difficult doesn't mean the information shouldn't be released. If we accept that the request is difficult as a reason to not release the records, then they'll never get released. Once that seed's planted, it's so unbelievably hard to come out of. It's something you see with agencies that never get held accountable to their lack of transparency.
It sucks, but the alternative is much worse.