I agree with this.It could be done, but is it cost effective ? Sovremenny-class was built around P-270 Moskit (3М80МВЕ version for China), everything else is secondary...they would use them for few more years paired with other more capable ships (as already suggested here) and then gradually retire them .
Any nation today still has to respect those eight missiles each of these vessels carry.
And particularly on the two later vessels with the Gadfly and the Kashtans they provide a credible layered air defense...and particularly if accompanied by either a Type 054A or a Type 052C/D.
I expect we will see those vessels for another 10 or 15 years continue n service with the PLAN.