Background: Between 2000-2024, over 35 African nations implemented competence-based curriculum (CBC) reforms promising enhanced 21st-century skills, employability, and educational quality, investing over $5 billion collectively amid strong advocacy from international development agencies. However, accumulating evidence suggests severe systemic implementation failures with troubling socioeconomic implications. Objective: This study critically analyzed CBC implementation systemic failures across African education systems and assessed socioeconomic implications for learning outcomes, educational equity, and development outcomes. Methods: A sequential explanatory mixed-methods design was conducted January-November 2024 across six African countries (Kenya, Rwanda, Uganda, Tanzania, South Africa, Ghana). Quantitative data included cross-sectional surveys of 1,848 teachers, 360 administrators, 1,200 students, 600 parents, and 240 employers using validated instruments (α=0.78-0.91); structured observations of 432 classrooms; and documentary analysis. Qualitative data comprised 144 in-depth interviews, 48 focus groups, and 12 comparative case studies. Analysis employed hierarchical linear modeling, structural equation modeling, difference-in-differences analysis, and thematic analysis using Stata 17, HLM 8, and Mplus 8. Results: CBC implementation fidelity averaged only 38.7±19.4 out of 100, with 62.7% of teachers demonstrating low fidelity (60%). Stark disparities emerged across school types: urban private schools averaged 56.1±16.5 fidelity compared to rural public schools at 31.4±19.2 (24.7-point gap, p