The Chinese PLAN brass already mentioned in their local media that Catobar Carriers is the way of the future.
If we based on that, then both ski jump carriers Liaoning and it's modified sister type 001A will be redundant in near future.
However, I personally doubt they can have 6 Catobar in 2030 time frame. If we look their media and internet forums, they plan to build Catobar in two class, the conventional power type 002 and nuclear power type 003, which they claim all will be based on EMALS catapult systems.
This which I doubt they can field six Catobar by 2030 time frame. Catobar is new system that they have to master on their own. They will not have know how from USN as partner..and despite all their espionage effort..this is the thing they have to master on their own.
Granted they have Liaoning and it's sister to master carrier operation, but we all know mastering Ski Jump carrier operation will be different with Catobar operation.
Say they manage to launch this type 002 as their first Catobar in 2020. It will make another 2 years to field it and mastered it. And there's another problem with their Catapults..they seems want to jump to EMALS all together and abandoned more proven steam ones..and this will take time to prove their EMALS worthiness in operation. Even USN still have trouble with Ford EMALS.
Considering that, I more tend to see, by most optimistic scenario, by 2030 they can only build 2 conventional type 002 and 2 nuclear type 003. However this nuclear type 003 will be another challenge, since they haven't build large nuclear power surface ships, let alone on the size of a carrier.
Their ship based nuclear reactor reliability is still on development, considering their SSN and SSBN operational is not as much and as far what Russian, US, UK and French has done so far.
So if this type 002 prove a success, I tend to see they will build four of them at most by 2030, while they still have to invest more time after 2030 to developed their Nuclear type 003.
Back to the topic, with 4 Catobar type 002, they will see Liaoning and it's sister as redundant, since PLAN will maintain more Catobar operating Aircraft. In that scenario..yes, selling Liaoning to Pakistan with all the Ski Jump operating Aircraft can be their alternative to get rid redundant capacity.
Again this is on the scenario of PLAN successfully having and operating more Catobar Carriers as the article mentioned.