I'm not an expert on this stuff, but my understanding is the real issue isn't the sensor, it's the lens you put in front of it. You essentially have two ways t

I'm not an expert on this stuff, but my understanding is the real issue isn't the sensor, it's the lens you put in front of it. You essentially have two ways to see smaller things from a fixed vantage point--put a longer focal length in front of the existing sensor, or put a higher resolution sensor behind the existing focal length lens. The problem is longer focal length gets big and expensive very quick, and existing lenses would limit the ability of a high resolution sensor. In many cases, high end professional camera with 36mp or higher sensors are hampered by the lenses that can't resolve that much detail. Now, maybe in a few decades the CalTech lensless sensor will be commercially available and will work well enough that we won't have to worry about optics anymore, and it will all be silicon, but CalTech's sensor currently has something like 16 pixels total, so it has a long way to go.