It's pretty simple.
I think with this...
My problem with the lack of Orb strikes isn't that it's missing. My issue is that it wasn't even touched upon in a single line of dialogue. Someone could have just asked, "Why aren't they hitting us from space?" Someone would look at them and shrug. I mean, they had to time to have a soldier think out loud about how the aliens might "be just like us", so it's not like they had a cramped script that wouldn't fit that one thing.