A typical ballistic missile has a conical warhead with a radar cross section at X-band of 0.01 m2. In contrast, the LRASM is claimed to be very stealthy – virtually undetectable. The USN has always had a healthy respect for sea skimming cruise missiles more than ballistic missiles. This is because the detection window for a typical non VLO sea skimming cruise missile is in the 15 to 20 nm region due to the earth curvature regardless of how powerful are your ship sensors. The LRASM further adds to this problem because it is not only VLO but its onboard ESM features dynamically allow it to navigate around the sensors of its targets and or escorts based on their electronic emission patterns. In addition, the LRASM can operate collaboratively in a swarm like manner through networking its multi-modal sensors and offering diverse observation angles to improve target identification. Using its onboard AI algorithm, it can dynamically retarget autonomously. In effect, the swarm protects each other by quantitatively overwhelming defenses when they operate through collective behaviour. Neither the Chinese or the Russian have anything similar because their design philosophy is simply brute force based on speed through a bigger missile to house more fuel. The next phase of the LRASM is to add EA and ECM onto its capabilities.
Btw there are different meanings to the word swarm attack. The traditional and most basic meaning is simply that a bunch of missiles are launched together against a target hoping to "swarm" it by sheer numbers, The swarming features of the LRASM is AI driven where they are able to conduct decision in real time and collectively through a network of data links to ether re-target or cooperate in attacks by sharing information and acting collaboratively.
I would disagree that an LRASM is virtually undetectable.
We can see small control surfaces like fins, and indeed the smallish missile body would generate UHF radar returns
So we can expect to see multiple AWACs and destroyers operating UHF Aesa radars at different angles. Then sharing the results with CEC and generating missile tracks.
The US has already demonstrated this with with NIFC-CA using Aegis and E-2s.
And if there is a competition between AI and ECM, it is the defending destroyer fleet which has much greater capability than a bunch of small missiles.
But just for argument's sake, let's say LRASM is as stealthy, effective and as smart as you say.
There is nothing stopping the Chinese military from developing an LRASM equivalent.
And if both US and Chinese LRASMs make the Western Pacific a no-go areas for ships, that suits the Chinese military just fine.
China has the use of land based aircraft and missiles to achieve its objectives next to the Chinese mainland in the Western Pacific, whilst the US only has Guam some 3000km away.