The NFL has been gaining popularity as you say for 50 years, yes. But don't kid yourself as to why the sport is head and shoulders above Baseball and Basketball. It is the competitive balance created by the salary cap. And if it disgusts you to see good teams disassembled then blame the management team that went for broke and sold out for a short term run. Luckily we have a management team that understands that is not how you manage a team.
I have no doubt that Kraft would spend big if there were no cap as would Snyder, Jones, Johnson and few others. But how would that be good for football? Do you think people in Kansas City get excited when baseball season starts? Hell about 20 fan bases in MLB know they have no chance to compete for the playoffs, let alone the world series every single year. How is that a good thing?
The NFL is the only sport where every team has a legitimate shot at making the playoffs and every year a team that everyone think will suck ends up turning it around and making the playoffs. You can't say that about Baseball or Basketball.
So no I wouldn't say that is a joke. The salary cap is the reason why the NFL sells out just about every game every year and can charge billions for tv contracts.