Retail cross-border payments remain costly and inefficient, especially for small-value remittances. We examine the structural drivers of the high costs that prevail despite recent technological advances, focusing on market structure, business models and compliance issues. Using the US–Mexico corridor as a case study, we evaluate how online platforms and crypto-based technologies have reshaped these dynamics. While these emerging technologies have the potential to reduce costs and improve speed, fundamental challenges relating to trust, regulation and operational efficiency persist. The full benefits of technological advances can be realized only if foundational constraints are addressed. We raise questions about whether such models can maintain advantages once they have been brought fully within the regulatory framework.