Given the likely ongoing limited number of aircraft carriers (out to 2035 as an example), it is more likely that the Navy will maintain PLANS 16 Liaoning and 17 Shandong as operational out to the medium term rather than dispose of them.
The Navy has demonstrated that it can well maintain its vessels, and that it is prepared to invest significant resources to upgrade vessels. Sometimes these are only minor upgrades, other times they are very significant.
As long as Liaoning and Shandong can remain operationally relevant, it is likely that resources will be allocated to maintain and improve their systems.
Given the nature of their propulsion systems, it is unlikely that the propulsion system will be significantly modified.
It is very likely that self-defence weapon systems will be updated, as well as sensors. While not inexpensive, these upgrades are unlikely to be structurally significant.
The remaining element of the aircraft carrier is its airwing. While it may be technically feasible for the Liaoning and Shandong to be fitted with catapults, it is likely to be expensive and not needed to maintain the ships as operationally relevant. It is very likely that the Z-18F ASW helicopters will be upgraded as required out to the medium term, and that the Z-18J AEW helicopters will remain capable in their role. Should the new naval stealth fighter be capable of operationally relevant performance off a ski jump launch, the Liaoning and Shandong may end up with greater capability than they currently have. There is also the possibility of stealthy UCAVs to operate off a ski jump launch. These last two factors could well play the major role in determining the longevity of Liaoning and Shandong in service.
Even without the capability of the CATOBAR carriers, Liaoning and Shandong should still be capable platforms across a number of roles, including: traditional aircraft carrier roles (that require less capability than a CATOBAR carrier), SSBN bastion defence, and ASW Task Force lead.
