Best to do research and know the situation before making a comment such as this. Now, I don't know exactly who you are refering to when you say others are pushing for a low cap, but I can take a pretty fair guess. Including those three you mentioned specifically, it is fair to say that your assessment of each individual ownership situation leads you to believe that those teams are hanging on by a thread.
Now, I don't know the status of most teams in the league. But I have a pretty good idea of one and it happens to be one you mentioned specifically, Atlanta. And you probably couldn't be more wrong. New ownership took over just a year ago; changes near the top were made, more money was given to spend on the team, etc. These new guys in charge are actually taking a hands-on approach, which is worlds different from the robotic-like orders give from previous ownership (AOL/TW).
I'm sure the new owners in Atlanta would like a decently low cap. Even with their new found spending, the payroll this year would have been right around $35M (no rollback in that). Safe in whatever event might occur. But they do seem willing to throw caution to the wind a bit and with a large group of successful businessmen in this new ownership group, they certainly aren't hurting for money.
Ask yourself this. Of the teams you had in mind, do you think there could be other situations that you don't know of in terms of a team's ownership, its attitude, its finances, its economic viability, and so forth and so on? That answer is a resounding yes. You jumped to conclusions to try and make a point, but it won't stick that way. Not enough meat on the bone.