"As much as the NRA would like me to believe that, I don't believe that to be true. If they disappear, another group will step up and take their place."
With all due respect, that shows absolutely no knowledge of the history of the Second Amendment fight.
The genesis of the modern NRA fighting for your Second Amendment rights began in the 1960s.
After the Kennedy, King, and Kennedy assassinations, there was an enormous movement towards unbelievably draconian gun control/bans at the Federal level.
NRA had, at that time, an office of maybe three people who handled the politicial end of things.
And at that time, there were no other groups fighting for your Second Amendment rights.
NRA did what it could to combat what finally became the Omnibus Crime Control and Safe Streets Act of 1968, and it got some of the absolute worst provisions removed from that bill, but it was still pretty bad.
Through the 1970s things became progressively worse for gun owners. I don't know how many of us remember the abuses that happened during the 1970s, but there were some really incredible ones.
At that time, NRA was still the only real player in town (SAF was founded in 1974, GOA in 1975, and it was a long time before they drew in more than a handful of members), and it wasn't the player that it would become, either.
Worse, in 1976 NRA's then leadership decided that protecting your Second Amendment rights just wasn't worth the effort. Apparently they thought that if all of the "bad guns" were outlawed, and we gave the politicians what they wanted, they'd leave us with our sporting guns and everyone would be happy. (That's a strategy that worked out just great for British and Australian gun owners, by the way).
That stance is what led Harlon Carter, Neal Knox, and others to seize control of NRA at the annual meeting of members, giving birth to the modern, pro-Second Amendment rights NRA.
The ugly truth is that had NRA not been around in the 1960s and 1970s as the ONLY organization to fight GCA 1968 and some of the follow-on legislation, and had NRA's old leadership been allowed to surrender, many of the rights and firearms that we enjoy today would be gone.