The liberals did not only arrive to "fill the void" as I implied. They indeed were here from the very beginning and led the revolution in many aspects. Some kind of vanguardism on their part existed I guess. But there was also people with a genuine social agenda (see my reply to @Sarcasm24).

The left in power had a strong tendency to send counter-revolutionaries under the guillotine. Libs quickly felling like they were being targetted + opportunist traitors who were very common in this unstable climate = one of the main reasons why they failed and moderates took over.