Perhaps at this point you can argue, that you totally expect this mental pattern to be reattached to some set of memories or some personality outside the Matrix.

There should be some universes in which the simulators will perform a controlled procedure specifically designed for saving me. This includes going to all the trouble of reattaching what's left of me to all my best parts and memories retrieved from an adequate backup.

Of course, it is possible that the simulators will attach some completely arbitrary memories to my poor degraded personality. This nonsensical act will surely happen in some universes, but I do not expect to perceive myself as existing in these cases.

It seems you are right that gradual degradation is a serious problem with QI-based survival in non-simulated universes (unless we move to a more reliable substrate, with backups and all).