Open-source technology has enabled RISC-V to emerge as a cost-effective alternative for processor manufacturers by reducing intellectual property expenses. A key factor influencing its broader application is the maturity of the RISC-V software ecosystem. However, quantifying this maturity remains challenging due to the complexity of the ecosystem. In this study, we introduce Sapling, an automated oracle designed to systematically evaluate the maturity of the RISC-V software ecosystem. Our framework categorizes the ecosystem into \emph{five} domains comprising \emph{thirty} software components, each assessed across \emph{six} dimensions. These evaluations are then aggregated within each domain and further analyzed through a cross-layer evaluation. Our findings indicate that while the RISC-V software ecosystem remains in its developmental phase, it is steadily advancing, demonstrating strong potential for sustained growth and broader industry application. Furthermore,~\emph{thirteen} key insights and \emph{five} strategic recommendations are presented to advance the maturity of the RISC-V software ecosystem. We hope that this study contributes to a deeper understanding of the maturity of the RISC-V software ecosystem and offers valuable guidance for its effective enhancement.