How did Middle Indo-Aryan changes simplify Sanskrit grammar?

Middle Indo-Aryan simplified Sanskrit grammar through several systematic reductions and structural changes:1

• Nominal System: The dual number was eliminated as a separate category. Additionally, the dative case was largely replaced by the genitive, except in specific instances like denoting purpose.1
• Verb System: The distinction between active and mediopassive endings was removed, as was the Old Indo-Aryan contrast between aorist, imperfect, and perfect forms. Finite preterite forms were generally replaced by the past participle, which agrees with the agent or object in number and gender.1
• Stem Simplification: Complex alternations found in Sanskrit were eliminated in favor of unchanging vowel stems. Furthermore, consonant stems were steadily transformed into vowel-ending stems, and infinitives were increasingly formed on the present tense stem rather than the root.12
• Phonological Impact: The deletion of final consonants and the simplification of consonant clusters necessitated these grammatical shifts, as the loss of distinct endings forced the language to rely more heavily on participial constructions and fixed stem forms.12