Breaking the Flat-Tax Path? Systems Thinking, Causal Loops and Professional Intermediation in a Romanian Household Tax Scenario

Differentiated personal income taxation shifts fiscal complexity away from the rate structure and towards the information that households must collect, interpret and document, which turns a question of tax design into a question of system behaviour. This article treats a household-based personal income tax, officially proposed in Romania in 2017 and never implemented, as an exogenous intervention in a path-dependent socio-fiscal system whose subsystems (taxpayers, professional intermediaries and the tax administration) are coupled through feedback loops of complexity, delegation and capacity. Twelve anchor statements extracted from institutional theory, agency theory, tax compliance theory and systems theory consolidate into five research propositions forming the dynamic hypothesis of a causal loop model with one reinforcing loop of complexity-driven delegation and two balancing loops of capacity substitution and incentive alignment, and the propositions are evaluated on survey data from 420 accountants, tax consultants and lawyers through Kruskal–Wallis tests with Dunn comparisons under false discovery rate control, equivalence testing, reliability and factor diagnostics, a multinomial logistic model and bootstrapped multicategorical mediation. Three propositions are supported and two partially supported. Operational time is assigned to professionals more often than to any other actor, accountants and tax consultants form a statistically equivalent ex ante intermediation bloc distinct from lawyers, and support for including accountants in the authorised architecture is not transmitted through individual service openness, since both indirect effects are null, although the nested response format of the eligibility item leaves collective professional interest untested. We conclude that, in the expectations of the professional layer, the feasibility of household-based taxation is a system property governed by the capacity substitution loop, whose operational capacity is supplied by the accounting profession.