I am comparing their performance {XRCDs vs CD) in modernly recorded album{eg.Audiophile voices}.
That may explain it. I doubt they get anything but the master tapes. If the master tapes are of jazz or clasical and already of very high quality sonics then I expect XRCD will be limited in what enahncements they can do (better noise filters, better dithering etc).
On modern pop/rock music though, XRCD might be able to do something with studio masters - these are often compressed in the mastering process as issued by major labels.
Note that it can go both ways with remastering. I have TOTO Essentials remaster that is worse than the orginal. I have a Duran Duran Rio album that is way better than the crappy original CD release. I have an MSFL Tom Petty Full Moon Fever that sounds slightly smoother in the highs than the regular CD (but frankly I prefer the clean sound of the original to MSFL's doctored sound). I could go on and on and on.
Unfortunately what sounds better may be a matter of taste. At low levels, Toto Essentials CD sounds snappy and aggressive ...unfortunately this has been achieved by audio compression in the re-mastering and, as a result, there is a lot of added distortion that becomes more obvious as harshness at higher listening levels.
I would expect JVC would never squash music deliberately like the major labels do these days - therefore my guess is that the XRCD are either very nearly equivalent (on a good original master) or much better (on a poor original master). So perhaps you get a mixed bad - depending on your music tastes - a big improvement or a minor one...
For example, remember "Frankie Goes to Hollywood" debut album...wow was that ever a great sound (thank you Trevor Horn) and it sounded just great on the major label CD releases....no need to fix that one - I doubt JVC coudl do a lot better with that as starting material!