Solid-state batteries offer the potential for high energy density and improved safety when compared to conventional Li-ion batteries, brought by replacement of liquid electrolytes with solid lithium-ion conductors. While concepts using polymer electrolytes have entered niche markets, transitioning to industrial-scale manufacturing faces major hurdles. Critical challenges include electrolyte selection (with different families of compounds exhibiting different advantages and drawbacks), compatibility with electrode active materials and interface engineering, processing aspects and long-term performance. This perspective outlines the current state-of-the-art and critical aspects across the main classes of solid electrolytes and a development timeline to raise solid state batteries' readiness and industrial uptake, from short-term interface stability improvements to long-term mass-market adoption.