A "primary" leader is only going to be a primary target for our enemies and will have a very short tenure. Small groups are going to be the order of the day against the government at first.
Considering the tens of millions of armed citizens in this country your one by one scenario would take several hundred years to complete, if not much longer, so that doesn't seem very realistic either.
Once the federal government goes full on tyrannical and tries to start rounding up firearms, you don't sit back and wait for them to come for you, you take the fight directly to them, and asymmetrical warfare won't be a pretty sight to say the least.
I think you underestimate the resolve of many patriots in this country.
A disorganized resistance will not be as effective as an organized one. Nobody these days (or a thousand years before) would even suggest that an army doesn't need a hierarchy of leadership. Someone has to see the large picture; the opposing side will have professionals doing that.
The purpose of the leadership is not to carry the banner in the front lines. The real goal of a leader is to help the men to do what they are supposed to do. In this situation the leader would be overseeing an intelligence network because you cannot win the conflict without knowing what your opponent is up to. Small groups (say, a group of ranchers) will be simply unable to gather that information because they are not present in cities where JBTs are sent from. At the same time, hundreds of supporters in cities, who see the deployment and perhaps even overhear the destination, do not know who in this or that area might need the notice. Who is going to build up a network of people with low power HTs and with iPhones sending coded messages? Not those ranchers, certainly; however a teenager who is familiar with technology can do it easily. A system of cells, passwords, reporting has to be established; what farmer is an expert in that? They will talk to a wrong man and the whole structure goes down.
Another very important area would be the PR war. All the misdeeds of a tyrant and his henchmen must be documented and published for the whole world to see. This is important - plenty of countries will have reasons, good or bad, to apply pressure to the dictator and to deny him the freedom of maneuver. No dictator today should be given time to send millions of citizens into concentration camps. With a smartphone in every pocket, everyone is a journalist these days. However "small groups" are not capable of presenting a coherent message to the world. They may not even have servers abroad - and that is a requirement for a successful PR campaign. Only the leadership can gather enough IT and Web specialists and establish contacts abroad, in neutral countries. A common farmer does not know how to buy a web hosting account in Sweden.
I do not deny that leaders may emerge. Probably that's the only way how leaders can be found. However the core message is that leadership is required, and the sooner it is formed - the better.
Considering the tens of millions of armed citizens in this country your one by one scenario would take several hundred years to complete, if not much longer, so that doesn't seem very realistic either.
Let's count. For example, there are 50 million people who refuse. (In reality I don't think there are so many.) Also let's presume that there is 1 million of LEOs of all kind (police, sheriff, national guard, regular troops, etc.) If each arrest takes two LEOs and 2 hours of time, each pair can do four arrests per day, or two arrests per day per LEO. That is 2 million arrests per day! The whole 50 million people will be arrested in less than one month. That is very realistic, time-wise. A better question to ask would be "where they are going to be incarcerated?" - and the answer to that plugs into the discussion above, about documenting the abuse and revealing the extent of tyranny.
I think you underestimate the resolve of many patriots in this country.
Resolve and support are orthogonal. The best fighter in the world can be lost in a forest without a map. Leadership provides maps. In an ideal case, a leader can just call for a general strike - and the whole country would grind to a halt. The tyrant would be forced to quit without any hostilities whatsoever, and it will take less than a week. A small group cannot achieve that.
You can look at AQ as an example of such a leader. They aren't leading in a good direction, but you cannot deny that they are reasonably effective in PR and in recruiting and in training. They develop and publish strategic plans, they design military actions, they procure weapons and ammo, they collect donations and put them to use. They are one of our opponents; however it would be unwise to ignore their strong aspects and disregard how they got there. Gaddhafi was controlling "small groups" for several decades; and then AQ waltzed in and conquered the whole Northern Africa in less than a year. A wise man uses every learning opportunity; that includes taking lessons from the enemy.
The command structure of "every man for himself" still may win, but the victory will be highly Pyrrhic. Organization helps reduce needless losses. Need to go to a certain city? You get a word about how to do it safely. A group needs materiel? The message will propagate until the resources are sent in. A raid is about to happen? There is nobody in the house. There is an arrest warrant on a certain person? That person disappears, and a completely different person, with different appearance and papers, materializes out of thin air 1,000 miles away. The history of the last century tells us that successful resistance networks were well organized; disorganized resistance was often wiped out.