Rethinking agrarian transition in Southeast Asia through rice farming in Thailand

•Smallholder rice farming persists and farm size remains constant, refuting the farm-size-transition hypothesis.•Variegated trajectories of agrarian transition occurring in the Central Plains and Northeast of Thailand are explained by an interrelated set of key dynamic variables.•These factors are access to resources, household farm labor, farm inputs, agrarian finance, and government support.•Our comparative data show how regional specificity and geographical proximity to advantageous factors shape variegated agrarian dynamics.