[unavoidable]

It probably has to do with the failure mode rather than actual rate of failure, although it may be perceived differently.

When digital signals "fail" (usually just minor interference or some power fluctuation), you usually just get a black screen or a picture that cuts in and out. When analog signals "failed" (in the same interference or fluctuation) then you likely got a distorted image/sound/colour for a few seconds but it didn't really interrupt your viewing experience.

It is an interesting observation that it seems in areas where there was still analog and digital transmission in parallel, that the "live" analog signal was "faster".