Why are there so few
good photos compared to reports? Simple. The rate of "saucer" UFO sightings varies independently from any photos taken. The relatively few genuine photos indicate that UFO encounters are brief. Floods are rare events, but they last for more than five seconds. Plane crashes are rare too, but the plane isn't going anywhere after. It's no surprise photos can be taken of the wreckage, etc.
Here's the problem with UFO photos: In order to record a UFO, you need to take notice of it. Then follows an escalation of hypotheses. It's rare that a witness thinks they encountered a craft/BOL/etc. at first glance. Considerable time is spent figuring out what the object is first. When the witness reaches a conclusion, the craft is long gone by then. Even if you were to record it, the quality is very poor.
Genuine UFOs aren't usually seen flying over urban areas where passerby are likely to have a camera on them. According to Vallée, there's an apparent
pattern of avoidance (Vallée 1990, pp. 3-4). It's an elusive phenomenon. So we can't expect photos to increase over time, nor should we.
Adequate-quality photos, let alone photos, are very rare for these reasons.
Think of the UFO as a rare species of animal. It's rarely photographed, but many photos have been hoaxed. It has a limited range of distribution, and there are more reported sightings than photos. Craft UFOs appear to few witnesses also.
Now, the number of photos/videos
alleged to be UFOs has definitely increased with the proliferation of cameras. Any statement to the contrary is either ignorant or a blatant lie. Look at any YouTube video. But no one disputes that plane wreckage is plane wreckage (in most cases). We don't know what "saucer" UFOs are. They could be alien, time-travelers, inter-dimensional, etc.
And no photo will convince a skeptic, so it's stupid to rely on that as evidence. We don't need photos to verify the reality of UFOs.