Metal-air batteries (MABs) have emerged as promising energy storage technologies due to their exceptionally high theoretical energy densities and potential for sustainable electrochemical energy conversion. Despite substantial research progress, their practical deployment remains limited by fundamental challenges associated with metal charge carriers and system-level design. Across monovalent (Li+, Na+, K+), divalent (Zn2+, Mg2+), and trivalent (Al3+) MAB chemistry, ion valency critically influences electrolyte stability, reaction kinetics, electrode reversibility, and overall scalability. Analyzing the general bottlenecks inherent in industry-mature Al and Zn-air batteries provides a solvable pathway for other developing metal-air systems. Achieving progress toward practical MABs across all ionic valencies requires synergistic strategies encompassing advanced electrolyte engineering, accelerated electrode kinetics, interfacial stabilization, and scalable system architectures. Addressing these interconnected challenges will accelerate the industrialization of high-performance, cost-effective MABs for applications ranging from portable electronics and electric mobility to grid-scale energy storage. This review evaluates the current state of the art, highlighting transformative solutions in mitigating critical bottlenecks essential for realizing the next generation of high-energy, sustainable, and commercially viable metal-air electrochemical energy storage solutions.