Of course CGL, there is another explanation in modern Ufology and that is-accepting a non-nuts n bolts explanation firstly- that whatever is behind the phenomenon, it shows exactly what it wants us to see, no more, no less - in fact one could argue that every single sighting of whatever craft in whatever situation, even aliens being seen etc, it's all by 'their' design and as such, as modern tech evolves and becomes smaller and cheaper, ostensibly making the capturing of countless great photos ever more likely, rather than the field gaining more evidence, it seems to be just as ever - just out of reach.
It definitely seems that types of UFO change with the times and so do reported close encounters, in fact it seems there are far, far less close-up landings, strange interactions with beings etc. I do not doubt cases such as Delphos, Kansas or Soccoro, New Mexico. Both are amazing witness and physical evidence cases that are extremely hard to debunk and it personally saddens me that in these days of iPhones etc these kind of cases seem to be reported much less. Will we ever get another Westall or Ruwa? Imagine a modern day elementary or middle school with a bloody great saucer landing at the edge of the sports field with 100+ youngsters crowding round for a long look? It would be on Youtube and Twitter etc in seconds - this being something the phenomena, I think, does not wish to happen yet, and so the phenomena stops putting on such shows. There must be very few schools worldwide where absolutely no kids have a camera phone. Even in very poor countries cellphone ownership is commonplace. Perhaps some Innuit-type people in Siberia, who have no network access, may be the last of people to whom an amazing landing display could still happen without the world getting real-time proof.
Even if someone is still resolutely nuts n bolts, such as Stan Friedman I think, it's easy to think any UFO occupants watching the Earth will be aware of our technology advances and seeing how they don't seem to wish to 'land on the Whitehouse lawn' yet, I doubt they wish to provide easy evidence. Which, for those of us in love with this field, is a real shame because it reduces the likelihood of any of us getting a class-A sighting of a daylight disc for instance. It seems high-altitude night-time shenanigans and simple but still amazing lights in the sky are the order of the day for now....I wonder if world governments put together a worldwide UFO-spotting grid of infra-red and night-vision cameras etc, maybe the phenomena will evolve even more into a form that makes such a grid impotent. It's always one step ahead it seems.