Hmmmm. The reason the frigates are being retired early, is because they have been run to something like twice their design life and to allow them to keep going would require very intrusive and expensive refits. Said refits would also take a very long time so the additional ship time available would be small. In other words, very poor bang for buck.
Unless I missed something, the idea that they can't be manned is a bit of throwaway speculation in the NL article, rather than the "fact" that some seem to be taking it as.
Interestingly, if you add up the complements of both carriers, the 19 nominal DD/FF, 11 submarines, 6 MCMV (plus spare crew) and eight OPV, you end up with about 8500 billets. Add in another 1000 for the 9 or so NAS and another 1000 or so for RFA and you get to 10500. From a trained strength of about 28000 including Royal. So easily a sea/shore ratio of 1:1. Which as we know means that it's not a raw numbers game as some are suggesting, less still caused (along with famine, pestilence, disease, poverty, global warming, crime epidemics and the cost of living crisis) "by the carriers".
It's actually shortage of specific roles particularly in engineering trades stemming from some piss-poor personnel policies and initiatives ever since Topmast. Compounded by an ever more prescriptive training system where the shortage of seagoing billets (see knackered frigates) is making it harder to grow those people.