But it had a radical element, which was entirely doing away with the a monarchical system (thought not a class system).
Haiti was far more radical in that it was a slave uprising. In that case, it was outside subversion that caused all sorts of problem.
I think you’re also underplaying just how tumultous the actual transition from monarchies to modern nation-states actually was. There were centuries of actual violence in Europe as these societies went from one kind of system to another (with no clear direction, actually). It was never a given that any of the enlightenment era ideas or postenlightenment ideas would take hold and bear actual fruit. This was not a slow evolution that happened, but a violent wrenching global process that brought the modern world into being. As such, it is not inevitable, and it can be made to work better for all of us. Thatcher was wrong when she said there is no alternative, because there always is. There is a reason why we’re still interrogating the various thinkers of the 18th and 19th century, because we’re still dealing with many of the problems that they identified and described.