I'm also a software guy but started in military grade hardware. You're correct. Stress testing alone on components and integrated modules will typically wreck

I'm also a software guy but started in military grade hardware. You're correct. Stress testing alone on components and integrated modules will typically wreck consumer grade devices in a hurry. Engineering hardware to operate in extreme conditions takes significant effort and iteration. Even little things like manufacturing solder joints with no weak spots is a big task. Plus there's a lot of cost for certification, which you need at all levels. The actual circuit design is usually the easy part