Yes, all true. The losses the OP is trying to get back happened during the original rip -- it's what you give up to get smaller file size, and there's no getting that back except to start with the full-quality source (the original CD) and re-rip to a higher bitrate with less loss. Ironically, if you re-convert a highly-compressed file (e.g. low bitrate MP3) to a less compressed format (other than lossless), you still lose more during the second compression.
Think about it this way (it's not totally analogous, but close enough for this example): if you photocopy a picture with a crappy photocopier, you can't restore the image by running the bad copy through a better photocopier. You just get a third image with some additional loss.
