No, this is not normal.
I had an even older NEC wide-gamut monitor with very similar specs which worked for me for 8 years. Even after all this time, its measured gamut was still very close to AdobeRGB. In fact, it stabilised so that validation didn't require re-calibration for years on end.
It is more likely that the colorimeter degraded, if you had a very different result with the same one years ago. But my Datacolor Spyder 3 lasted those 8 years and showed consistent results, and was later verified with a new Spyder 5.
I don't know specifically about your X-Rite model, but many older calibrators are not well compatible with the wide-gamut displays, esp. with the newer LED ones: they cannot correctly measure the most saturated colours. You need to check if NEC specifically lists your model as compatible with this monitor.
To partly mitigate this problem, SpectraView II can skip measuring the primaries (the most saturated colours by definition) and rely on their supposed values. This is controlled by the last option on your last screenshot. Try to switch it to Automatic and repeat calibration, and see if you have a different result. It seems that only the green measurement is affected.
Also check the correction curves after you re-calibrate (the 3rd tab on the first screenshot). On a good NEC (or any professional) monitor, they should be smooth and almost linear.
Finally, although this must be unrelated to the problem, I don't know why one would use the 6000K white point. Apparently this is meant to be sort of a compromise between the print/art (5000K) and standard display (6500K). I would rather recommend a proper standard setting, most likely 6500K for you.