Perhaps the technology is mature and no astounding improvements will be available. Maybe it is like a knife. Can you buy a new knife each year which is thousands of times sharper than your old one?
Digital photography did reach by 2016 the same subjective level as digital audio did back in the 1990's.
Once digital recording technology managed to exceeded human hearing range by a wide margin, any further improvements simply failed to create commercial demand. Hands up, who owns SACD or DVD-Audio disks or players even though they offer way much better dynamic and frequency ranges than even non-compressed CDs?
As a matter of fact, quality has since been scaled back dramatically because almost all music is now consumed at "128kbps mp3" level. Customers simply care more about convenience than quality as long as the latter stays at acceptable level.
For example Sony has released A7R IV which exceeds human visual perception even in those couple of remaining categories. This camera claims to have 61MPix resolution and 15 steps dynamic range and how does it compare with human eye?
1) Cameras have topped speed of human perception for the last 120 years. It has been possible to freeze events which happen so fast that human eye can't see them at all.
2) Manufacturers must add permanent UV and IR filters to sensors because inherently they capture wavelengths which human eye can't see
3) For at least 10+ years, sensors have been able to capture more hues of red, green and blue than what we can see.
4) Dynamic range of human eye is often quoted to be 15 stops but this is tricky. If you look at a landscape scene with bright sunshine and dark shadows, eye adjust dynamically to each spot and human brain creates a full image out of these correctly exposed patches. Our vision is sort of HRD image and only this way we get 15 stops.
5) Central vision is roughly 55 degrees which is equivalent to FF 43mm lens. Human eye can capture details extremely well but only at an extremely narrow cone. However, when we move our eyes in this 55 degree area, brain once again patches these sharp spots into one full "sharp" image. If resolution is calculated based on shapest spot over the whole central vision area, we'll end up with 57MPix
So there you go. There has not been any real development in ILC sensor technology for years because you need a fully equipped laboratory to see any improvement in picture quality. Especially FF cameras have reached the SACD Audio point. MFT sensors could do with one more major upgrade round to reach the same level, though. In reality the perceived quality of any photograph is more about selecting the correct shutter speed and focusing on exactly the right spot at exactly the right time with appropriate DOF (which is purely subjective, not technical parameter)
Disclaimer: human vision works more like a video than still camera which makes any comparison questionable at best. Breakthroughs in sensor technology would enable us to take spectacular images at almost total darkness or record 10 000fps video with an entrly level FF body but they would no longer improve typical pictures or video which are shot under normal conditions.
