Commodore only supported Kickstart 1.3 on the CDTV, and while it is possible (with effort) to make 2.x and 3.x work on it, these are areas which Commodore never explored (they shipped the A570, which plugged into the A500/A500+ instead). We'd have to do our own research and QA work, and this boils down to how much manpower is available.
Things looks slightly more rosy for the CD32 for which we at least have the official Commodore ROM components at hand, last built in 1994. We could build a working ROM from those components (with effort), but we currently cannot rebuild these components from the source code.
Not being able to build ROM components from source code is a big issue since we cannot easily test and, if needed, debug and update them. 24-year-old code which was never updated is bound to be trouble and would need to be reviewed.
We found and fixed scores of operating system bugs which neither Commodore nor the OS 3.5/3.9 project work managed to spot and address in the past 24+ years (some are even older, going back 33 years). If you buy the OS 3.1.4 update, then you should expect that errors will be addressed and that the overall quality of the operating system will be improved.
We cannot currently deliver on these promises for the CDTV and CD32 platforms, which is first and foremost a question of available manpower. Taking care of the desktop computers (Amiga 500/500+/1000/2000, Amiga 3000/3000T, Amiga 4000/4000T and Amiga 1200) is already quite the challenge.
If you want to see the CDTV and CD32 supported in the future, it seems that the only way forward is to grow our small development team. Join us if you want to see CDTV and CD32 support taking shape.