Largely yes, but it should be noted that the NFL have a very good, centralised, official ticket re-sale program for season ticket holders. So while all games are largely sold out for the full year and big games between traditional rivals are pretty much impossible to get a good seat, for lower billed games it’s actually pretty simple to get a good seat because plenty of season ticket holders choose not to go to all games. Why did I go and sit outside in Green Bay and Chicago for 3-4 hours during the first week of December? Because they were games I could get excellent (Lambeau Field on halfway) and OKish seats (Soldier Field in end zone corner but only half a dozen rows back) on consecutive days at face value via the NFL Ticket Exchange.
Leigh.