Likelihood decreases down the list with the last being almost impossible. It was a near miracle that 1776 both succeeded and made things better.
Was it better? How can one calculate the lost opportunity cost of the Confederation lasting 200+ years? It may well have worked out better.
Revolution impossible? I don't think so.
Almost everywhere one turns now developers are quoting Kelo and taking property. Even the guy with his pants halfway down his butt understands the threat losing their home poses, especially since condemnation of homes for those that "won't play nice" with prices is the norm.
AMT taxes are going to bite more and more of the middle class every year.
As property values inflated wildly, estate taxes will increasingly affect the middle class.
People are spending so much more on food, energy, insurance, etc, yet the government tells them there is no inflation, and costs only increased 2.5% for the year.
Summary: Everywhere middle-class America turns, things are rougher...
keep hitting them in the wallet, where it hurts, and you will get violence. The middle class won't go silently into the long night.
Chances of making current government go away? Quite good.
If 2 idiots with 1 rifle loaded with Walmart ammo, who kept calling police in an attempt to turn themselves in, and who were interrogated at no less than 10 police checkpoints could cause panic and bedlam around the nations capital city... well.. imagine what any random assemblage of 10 folks from this board could do to 1-5 cities, or a state. What if they started 30-days before April 15th and targeted tax preparers?
Chances of replacing it with something that won't turn back into the same (or worse) mess? Very low.
Too many competing interests. You'd have the skinheads, panthers, no end of wackos/hatemongers out there trying to co-opt, take credit, or do something and discredit good folk.
The only way to be sure of good results is another secession or going back to the Articles of Confederation. Any other outcome will likely be far worse.
Now understand the first time around, things broke out roughly this way demographically:
1/3rd for Revolution
1/3rd for Loyalty to King
1/3rd could care less
Next time? Since governments always get what they subsidize (government workers and unemployed welfare collectors), it will be:
10% for "something else"
40% scared crapless
40% scared the checks won't be in the mail, ratting out the 10% whenever possible
The only possible advantage the 10% have is 5GW, and the fact they will be 10x more pissed off than the founders ever were, because
that is what it will take to get them off the couch.