I don’t think anyone is assuming J-10Cs are replacing all the mirages, if they are then they’re surely wrong. but one has to assume the mirages are going to be retired before 2035 or even 2030 (specifically the ones that have absolutely no upgrades). So in that case what would be their replacement? It would be pretty difficult to keep the entire mirage fleet in the air till 2035 without any source of spare parts now.In my opinion the J-10 is NOT a replacement for the Mirages for the following reasons:
1. The Mirages are PAF's strike element, capable of carrying various SOWs. To the best of my knowledge we are not buying the various SOWs that come with the J-10 - we have heard a lot about PL-15's and AESA's.
2. Azm is envisioned as a heavy-weight strike aircraft - and in my opinion will be the replacement to the Mirages.
3. There's an F-16 shaped gap in PAF's numbers - so IMHO the J10s are coming to augment the F16s.
That being said aircraft don't HAVE to replace another aircraft one-to-one so saying x is a replacement for y is always just a rough statement.
Surely, the J-10Cs can be put into newly raised squadrons if they’re not replacing anything, but it just seems more realistic that they will replace some of the older mirages (which I don’t think PAF would be using stock mirages for long range strikes anyways, maybe only for CAS/Normal bombing runs, which Any other aircraft could do better, while the upgraded ones can still be used for SOW and RA’AD delivery).
To put it shortly, I just don’t see what else the mirages can be replaced with, nor do I see how they will physically be able to serve till 2035 (probably longer if Azm has delays) without becoming safety hazards and increasingly hard to maintain. (Again, specifically non upgraded and older mirages, there’s a big difference between a ROSE mirage and a stock mirage).