With Harry gone, the purebloods running the Ministry are going to face a dilemma. Do they support their peers who are Deez and keep their bribes coming in or do they take a stand, execute the captured and convicted Deez, and train up the "common people" to fight? The first risks a sociopath coming to rule while the second risks converting the "sheeple" to aware and involved citizens which could be as detrimental to purebllod rule in the long run as Riddle's more immediate win would be. An arguement could be made that, either way, the current pureblood elite are hosed.
Hey again, Cat! Excellent questions, all!
IMHO, People are basically lazy. The problem as I see it, is that the wizarding Britain is hopelessly corrupt. Most would prefer to take their gold and look the other way instead of doing something about the problems. The purebloods will simply play along with Voldemort, thinking they are exempt from his pogrom, since most agree at least partially with his rhetoric. They won't risk themselves for anything, for a few more years, preferring to keep their perks. By the time they come 'round, it'll be too late.
Those who don't agree with Voldemort will be 'eliminated'. After all, Dumbledore showed no compunctions at all at destroying three of the oldest pureblood families, for his idea of 'the greater good', why should Voldemort be any different.
Instead of forming a real army, coordinating with the law enforcement agencies, and instigating real penalties for those marked, or asking the world at large for help, Dumbledore's solution was to select a sacrificial lamb, and hope that that Lambchops would play along. I believe this is why he refused to train Harry for his impending date with the scaly dude. He had sixty years to deal with Riddle and instead of taking decisive and permanent action, he diddled it away, pretending to be the epitome of the light.
What they need now, is enough people to band together and say: "enough is too much!" Remember, guerrilla warfare is the most effective method of reducing an army to ruin. Maybe there would be a Robin Hood, or a Zorro for them, but I doubt it.
In either case, I agree. Whether Voldy takes control of the wizarding world or not, the current crop of purebloods are doomed. If for no other reason than the constant inbreeding. Most, if not all, of those families are within three generations of incurable genetic defects.