Revolution and the historical application of the Dictatorship of the Proletariat have resulted in more democratic institutions being put in place than what previously existed.

Social Democracies are not Socialist, nor are they trying to be Socialist. They still depend on Capitalism, and exploitation of the Global South. They are also seeing rising disparity and weakening worker protections over time, because reforming a Capitalist state into something better over a gradual process is extremely difficult.

History's most notable democratically elected Socialist was couped in 2 years, Salvador Allende, with the help of the US.