Marxism-Leninism also has an inevitable endpoint once production is sufficiently developed that the state is no longer necessary as the conditions of reaction (such that create the grounds for rival classes to arise) have been abolished.

Leftists differ from their political rivals by recognizing the inevitability of history. Even social democrats think they can keep going indefinitely.

Radical liberals are conservatives the same way that monarchists hung on to the immortality of political systems that have nothing left to contribute.