While PLA is much stronger than the Libyan army and can deter surface combatants to keep a distance from the mainland initially, Tomahawk has a range of 1000km+, can PLA be a threat to a modern fleet, most likely a CVBG, 1000km+ from the mainland?
The PLA most certainly can threaten a modern fleet over a thousand miles from the Chinese coast, if they can find them. If the PLA can solve the key issue of being able to find hostile warships that far out, then they most certainly can launch a saturation attack capable of taking out even USN carrier battle groups.
Hostile subs - yeah that's a real problem, probably will remain a problem for quite some time, and some very quiet subs carry loads of Tomahawks.
Only the few SSGNs are they real threat with regards to Tomahawks. These can get their missiles closer than surface ships and so give the PLA less time to react. However, considering the size of China and the assets available, if the USN launched all their SSGN missile complement, chances are only a handful of those missiles will reach their intended targets.
Tomahawks are used to achieve air superiority by taking out air defenses and key assets, they are quite often used before air superiority is achieved, and it has proven itself over and over again.
Proven itself against adversaries with absolutely no chance of successfully defending themselves.
How can the likes of J7 be an effective measure to counter mass cruise missile attacks? Shoot them using PL-9/PL-10??
PL9s and PL10s would be a waste on tomahawks. These are massive subsonic missiles flying in straight lines with zero self defense capabilities. They are probably easier to shoot down than target drones or towed targets.
Cruise missiles like tomahawks are optimized against ground based radars and defense by exploiting terrain to avoid radar detection from ground based radars. With AWACS, especially AESA AWACS, and with the tomahawks coming in over the sea with no terrain to hide behind, they would be sitting ducks and it would end up as a massive turkey shoot if anyone tired to gain air superiority over China with just tomahawks. You will run out of tomahawks long before the PLA's defenses or capabilities are degraded in any meaningful way.
Point defense systems: Tomahawks will probably be spotted by radars (some latest cruise missiles have stealth features, but let's not make it too hard for China, for now...) - PLA's latest SAMs (not the long range ones) and AAA could be effective to a certain extent - but they can only defend a small area, and we know Tomahawk users use the missiles generously. Can the point defense systems handle several Tomahawks at the same time? 5 missiles coming in short intervals, if PLA could intercept 80% (that's quite impressive...), 1 still hits the radar station and will weaken/disable the SAMs, and it gets easier to penetrate the air defense.
THawks are only good against fixed targets. As has already been pointed out, the PLA prefers mobile radars. THawks will not be used against SAM radars.
What more, Chinese SAMs and radars work together with each other as well as AAA. You have long range missiles like the S300 and HQ9 protected by medium/short range missiles like the HQ7 and Tor, as well as AAA. Its going to take a hell of a lot more than 5 THawks to take out a PLA SAM radar even if you knew where to aim those THawks at.
Other high value targets like airfields and munitions dumps/factors would likely have CIWS like the LD2000 deployed. That is a naval grade CIWS designed to shoot down multiple cruise missiles exactly like the THawk within a very short time frame.
The PLA also has a massive range of MANPAD carrying vehicles designed specifically to take out cruise missiles and attack helos.
Speaking of targeting, THawks are highly dependent on GPS, especially for use at the edge of their range envelope. Even if we exclude the possibility of the PLA simply taking out those GPS sats, the Chinese should easily have the capability to heavily jam GPS signals when they want. Even if they cannot shut down the system that way, they should be able to degrade it.
Long-range SAMs - if they are effective against cruise missiles, how many S-300, S-300PMU and HQ-9 China can deploy in a certain area? And we do roughly know where they are currently deployed - what about those vast areas with coverage? And are they really effective against cruise missiles? I hope someone knows.
The top end missiles would likely be saved for higher value targets, or maybe to shoot down the odd cruise missile that slipped through and is threatening a really high value target.
CIWS is effective against slow cruise missiles, however we don't see a lot in the army. Key assets including radar stations and SAM batteries need to have adequate CIWS protection.
There is the LD2000, and modern AAA can be pretty close if not better than traditional 20/30mm CIWS with newer guns, radar guidance and smart munitions. All of which China is known to have or is in advanced testing of.
And...we haven't considered stealth fighters and stealth bombers that can take the lead in air strikes.
The only stealth fighter in operational deployment anywhere now or in the near future is the F22. Not only will it struggle to even reach China from US bases even with tanker support, it can only carry two bombs, at the cost of the number of AA missiles it can carry. If the USAF is desperate enough to try using F22s as a leading penetrating bomber, they lost the war before a shot was fired.
The B2 is a real bomber, but it would be a massive risk to send them in against a fully functioning integrated modern air defense network with a massive modern fighter force backing up the ground based stuff.
The B2 only reduced radar detection range, it is not invisible to radar. Get a radar close enough, and it will show up. What more, the B2 is optimized against ground based radars. How stealthy it is from the air is debatable, especially against powerful AESAs of AWACS specially designed to hunt small RCS targets.
The B2s are so expensive, rare and have such symbolism that they will only be deployed when there is an extremely low risk of them being shot down. They will only be sent in once the PLA's defenses have been seriously worn down and significantly degraded. But that's going to be a very hard and costly thing to do purely on the military side, and only the US has a realistic chance of doing it at all. Even then it will cost the US dear to do so.
