The roots of the revolution, according to Dickens, are rapacious license and oppression by the nobility. "Crush humanity out of shape once more, under similar manners, and it will twist itself into the same tortured forms. Sow the same seed of rapacious license and oppression over again, and it will surely yield the same fruit according to its kind" - P347, Book III, Ch15. Dickens, who lived in England where there were many unjust punishments and immoral actions by high ranking officials, was basically saying that the things that fueled the revolution in France, the crushing of humanity and rapacious license and oppression, if used in a similar manner somewhere else would have the same result. In this case he was probably thinking of his native country of England, but in truth it could happen in any country that practiced the same methods that France did.
The peasants in France were beaten down by the nobility and treated like the scum of the earth for many years. It is surprising that the revolution did not occur sooner than it did. It is presumable that the reason that the French revolution was so bloody is that it was so long in coming. The rage and hatred just kept building and then it finally popped. Like blowing up a balloon, it will pop and all the air will gome rushing out at once after too long but you can let the air out gradually through the place where you blow it. If the nobility has lessened the oppression and created more humane environment then they probably would not have lost their heads. The strength and will power of the poor is far greater than that of others and the peasantry in France clearly had a greater will and strength than the nobility. ""There is prodigious strength in sorrow and despair" Pg.306, Dr. Manette