W.M. Lindsay (1858-1937), Syntax of Plautus
(1907; rpt. London: Bristol Classical Press, 2002), p. 3 (§ I.1):
The rules of Latin Syntax which prevailed in the classical period, e.g. that quamquam and temporal quom govern the Ind., quamvis and causal quom the Subj., so often fail us in reading Plautus, that Plautine Latin at first sight appears to be regardless of rules. This appearance is partly due to the fact that Latin Syntax obeys the Darwinian law of the 'survival of the fittest.' Out of a great variety of constructions possible in the time of Plautus, only one or two favoured types have survived to the classical period. While Plautus, for example, puts the Verbal Noun in -tus to a variety of uses, e.g. spectatum eo, spectatu redeo, pulcher spectatui, facile factu, etc., two of these, spectatum eo and facile factu, survived the struggle for existence and became the First and the Second Supine. Again we find in early writers quo Abl. Neut. used with magis in affirmative, with minus in negative sense, and accompanied by the Ind. when a fact is stated, by the Subj. when an intention, e.g.
Ter. Phorm. 877 immo etiam dabo quo magis credas,
Eun. 737 quo intellexi minus,
Andr. 197 fallaciae . . . quo (nuptiae) fiant minus. Out of all this variety emerges in class, Lat. the conjunction quominus governing the Subjunctive and associated with Verbs of hindering.