Veracity of this news aside, it looks like it will come down to sensor network and computation power for the defense. Need a comprehensive, sensitive sensor network to take in lots and lots of readings, pretty fast network to gather/transport the readings, then do tons and tons of computation to tell real threats apart from decoys using those readings.
Reminds me of the submarine tech race. Running “silent” used to be enough, but then given increased computation power, what used to be “silent” also get exposed under intense DSP scrutiny.