They lived under the divine right of an Emperor after, the whole point that it didn’t work! And then they had another one, which resulted, you guessed it, in another monarchy.
For those who survived all of that, by some divine miracle, absolutely nothing changed. There was transition of power, sure, from one dynasty to another, but is that what we really can call a positive outcome of all the countless beheadings?

If we look at the previous time gullotines were used, there was something called Reigh of Terror which, after enormous, egregious amount of indiscriminate murder, ended with pretty brutal dictatorship who immediately started a world war (and obviously lost).
Nothing of that sounds fun.