When is a cart past its prime?

I have a Grado Reference Platinum mounted on a Technics SL-1200 Mk5 that I've been using for almost three years now. I feel like it doesn't sing like it used to. I've given it a lot of attention; aligning it till I was blue in the face, cleaning the stylus every record, dialing in minute changes in VTF/VTA. I feel like I'm doing everything to wring every last drop of performance out of it yet my older (but possibly less used) Grado Green trounces it. I've switched the two back and forth from the Technics to my Rega P2 and in both set-ups the Green edges out the platinum (less so with the Platinum on the Technics). It was not the case when I first got the Platinum. The Green is doing a great job of detail retrieval and delineating voices/musical lines where the Platinum falls flat now. I was blown away at first by the Platinum's dynamics and now they're somewhat m.i.a. Perhaps I'm lamenting a little bit the passing of a great cartridge but is there any hope?