They're not, they just fucked around or prioritised other things thinking that they could coast by on the same formula that Witcher 3 had. The thing is that the diorama works fine in Witcher 3 because the player has no expectation of how a dark fantasy village should work as a sandbox. It's just a bunch of small village people milling about. Works fine. More or less the same for the medieval city too. The shallowness of the world doesn't hurt it.
A modern setting though? And with expectations of the genre? You can't claim to be making AAA and then not really meet the standards that even small studios have met.
They're not, they just fucked around or prioritised other things thinking that they could coast by on the same formula that Witcher 3 had. The thing is that the diorama works fine in Witcher 3 because the player has no expectation of how a dark fantasy village should work as a sandbox. It's just a bunch of small village people milling about. Works fine. More or less the same for the medieval city too. The shallowness of the world doesn't hurt it.
A modern setting though? And with expectations of the genre? You can't claim to be making AAA and then not really meet the standards that even small studios have met.