This paper examines the evolution of Micro-Electro-Mechanical-Systems (MEMS) technology by analyzing high-volume MEMS products introduced over the last several decades. It covers MEMS devices widely used in high-volume applications, as well as MEMS mirrors and their role in optoelectronic applications. The discussion of non-optical MEMS applications highlights well-established products such as accelerometers, pressure sensors, microphones, speakers, and silicon timing devices, each shipping in billions of units annually. The focus then shifts to MEMS mirrors, emphasizing their critical role in opto-electronics. Key applications in this space include vector graphics laser projectors (VGLPs), mixed reality/augmented reality (MR/AR) solutions, free-space optical communication (FSOC), MEMS mirror for optical switching for data centers, and MEMS mirror systems for humanoid robots. Finally, special attention is given to the current state of LiDAR development efforts.