As conditions get worse and worse, analog transmission results also get worse and worse, while digital doesn't change. At some point, however, the digital system's error-correction capability can't keep up with the worsening conditions, and the system fails. At that point, without improving one iota indeed, as the results continue to degrade analog suddenly leaps ahead of digital and stays ahead until things have gotten so bad that a viewer decides the horribly degraded pictures and sounds are no better than their absence. That is why analog television works. It's also why many people use cable TV, satellite, MMDS, OVS, VDSL or other alternatives to analog television transmission.
Cable TV has flaws.
Analog and digital satellite systems have flaws. MMDS, OVS, VDSL and all the rest have flaws, too. Anyone could easily expect, therefore, that DTV would have flaws, too. DTV, however, was set an impossible task for any digital transmission system. It was to duplicate analog television coverage.