Ah the perennial PJ problems rears its head on many subforums on Flyertalk
That is, pyjamas not private jet!
However, and I totally appreciate why one would like to have free PJs given on board because everyone likes a freebie and they are quite nice to have, but if it is such an important part of the travelling experience, why would you not bring your own? Is it not unlike passengers bringing their own noise-cancelling headsets instead of the airline-issued one?
Wouldn't the money spent on giving out frankly disposable (to the airline) pyjamas be better spent on things like investing in new hard product or catering? After all if the pyjamas cost 5 USD, that would be a significant uplift on the catering budget...!
As to the amenity kit, I agree a cosmetic refresh should be in order every so often, if only for the marketing.