I think there’s just not enough police around to pull up those with lights out and those that are around I’m not sure are bothered.
DRLs and illuminated dash’s are certainly contributing to people not switching lights on. And in poor vis daytime I’ve inadvertently driven with no tail-lights like Glos Guy says. I too find it incredulous that manufacturers put only front DRLs on? Years ago Volvo had sidelights AND tail-lights coming on upon starting.