This is a thing people say a lot, implying that there were some mistakes from 2016 that should be learned from, but everybody involved in 2016 election season coverage thinks they did a great job and the same people think they have done a great job since the election and they think they are doing a great job now.
It's the people who regularly say that who have learned nothing. The lesson is these reporters don't see their job as what you imagine their job is, or how they portray what they want you to think their job is, because they are dishonest career climbers and not the beacons of truthtelling.