Economics was less developed and (possibly) fewer smart people had a basic grasp of the field. (Some good arguments against Marxist economics already existed but weren’t widely known).
Interestingly, the oldest of the bunch, Bertrand Russell, had been writing criticisms of Marx as early as 1896. In his lecture “Marx and the Theoretical Basis of Social Democracy” he provides several arguments against Marxist economics, concluding,
We have now discussed all the most essential points in Marx’s economic doctrines, and have seen that none of them, as a theory of what is, or of what necessarily will be, will stand a thorough criticism.
Interestingly, the oldest of the bunch, Bertrand Russell, had been writing criticisms of Marx as early as 1896. In his lecture “Marx and the Theoretical Basis of Social Democracy” he provides several arguments against Marxist economics, concluding,
Perhaps some of his work outside of (mathematical) logic was worth reading or hearing then.