Looking at this site, are there any interesting activities going on miniaturizing cameras? Is the research stalling? The papers here are at least 8 years old. Besides Avi Loeb any other prominent researchers?
Project Breakthrough Starshot aims to reach the Alpha Centauri system within the first half of the 21st century, with microprobes traveling at 20% of the speed of light propelled by around 100 gigawatts of Earth-based lasers. The probes would perform a fly-by of Proxima Centauri to take photos and collect data of its planets' atmospheric compositions. It would take 4.25 years for the information collected to be sent back to Earth.
A couple things:
First, so far as I can tell, their hope is to eliminate the need for any kind of lens by ensuring the sensor pixels are spatially aligned well enough to be in-phase (or at least fixed-phase). Essentially this becomes the equivalent of a phased-array radar sensor but at 1/1000 the wavelength (millimeter vs micron). It's not particularly easy to find materials and electronics that will allow you to measure the relative time-of-arrival at each pixel to within a fraction of visible light's wavelength.
Next headache: There's a practical limit to how thin a pixel can be and still have a decent quantum efficiency (percent of photons incident which generate signal). That may well be one of the limits which has been reached, and thus why no significant overall progress on this theoretical project.