hundreds of kms of altitudes mostly applies to ICBM. why will ICBMs fly near equator where most of the time ships are parked. new generation of smaller air launched BMs, ASM, ARMs are as fast as hypersonic projectiles that can fly high and fly low at sea surface in same flight and far manevorable for over size heavy SAMs.
The problem for ship based air defence system is that Radar and TEL are combined into one big structure.
you make one component bigger several other components are also need to be enlarged all the way to resupply ships and manpower.
now this manpower constraint may not apply to China.