There are a lot of variables that would make such studies very difficult.Of your two takeaways, the second one strikes me as the more useful, because it's actually measurable. Camera resolution, sensor sensitivity and the number of devices in circulation have all improved by orders of magnitude since the 1950s, so if image quality of UAP reports has stayed flat over that period, that's a quantifiable trend rather than an impression. Has anyone tried to plot it?
A person with a fixed focus film camera with only 20 exposures on a roll of film is less likely to use up one exposure on a hard to distinguish blob in the sky than a person with a digital auto-focus camera that can store thousands of exposures is to click the shutter button.
So not only far more cameras today but far more likely that a person with a camera will try to capture an image. Thus lots of indistinguishable points of light captured today that might actually have been seen in the past but not photographed.
Perhaps more close-up saucer photos in the past than today, but many of the "good ones" were probably pie plates suspended from branches with string. Not so many close-up saucer photos today because they would be harder to fake? A study of what the UFOlogists say are the best photos of the past versus those of today?