AWACS question

I’ve been reading up on various AWACS platforms. The E-3 Snetry has set the standard since it was introduced in the ’70s and it has been upgraded and its performance enhanced thru the years. Compared to the more modern PHALCON using AESA tech, its claimed that the R3 suffers because its rotating mechanical radome only updates target tracks every 20-40 seconds vs only 2-4 seconds for the AESA.
How serious a drawback is this for the E-3? A Mach 3-4 missile can travel quite a distance in the time it takes to update its position.