I wonder if they were similarly blasé when companies started implementing policies to actually stop them?

That kind of argument only works where stopping the behavior is cost free, the main reason most places didn't do it before was because the number of people doing it was low so the cost of actually tracking returns rigorously outweighed the benefit of low friction returns for the 99+% of customer who weren't abusing the system. When more people start creating large numbers of returns suddenly the amount of losses they create become enough to care about stopping. (Or it becomes a low hanging fruit to squeeze more profit out of an existing business, spending customer preference/loyality for profit by cutting a small waste center)