The Falcons courted Chris Long, but in the end, he was drawn in by the siren song of Bill Belichick.
Long is over 30 and coming off a couple of injury marred years, but he's a talented pass rusher and stout run defender who was a major asset for the Rams for many years. The Falcons showed genuine interest and hosted Long for a visit, but it appears Long bought in to the Patriots' contract offer and philosophy, particularly after Chandler Jones was dealt and a starting job opened up.
I think it's fair to argue, as many have, that Chris Long would've been little more than a high-upside gamble for the Falcons, considering it has been a couple of years since he was truly effective. It's also true that the Falcons could use any pass rushing help they can get, and certainly were interested in seeing whether Long could have bounced back.
Atlanta's got a decent defensive end rotation, but will likely be shopping around for one more player to add to it, whether through free agency or the draft. I'd wish Long luck, but I don't like the Patriots.