They still try. They still predominantly target fields of easy targets rather than competent targets that can fight back because that allows them to pad their killboards. CCP watched retention drop off of a cliff after mass wardecs and brought in the war changes to try to correct it and to an extent they’ve succeeded, but ultimately the problem has always been one of target selection.
The vast majority of war groups are predominantly poor PvPers that couldn’t handle a balanced fight and so they select the weakest targets and that’s newer, less experienced players or null groups so they can pick off stragglers autopiloting through highsec. If they wardecced a half-decent PvP corp they’d get their backsides handed to them.
I had this discussion with a member of one of them a while back and suggested that if they want better combat that they target corps who actually want to defend their structures and gave them a list, and they were pretty much blue with all of them.