You are right, there are other potential benefits, potentially dozens, but personally I akin it to missing the forest for the trees.
So often, in many aspects of life, we get so caught up in making things perfect that we won't just accept good. You've probably heard the aphorism "Perfect is the enemy of good."
It would be nice if there were loads more benefits we could harness from increasing airflow, but I just don't see it, and I haven't seen it or heard of anyone else seeing it in the decades I've been part of the hobby. It doesn't mean it doesn't exist, it might just mean it hasn't been discovered yet.
I will touch on a few of your points, not to argue them, but to give a bit more perspective on them.
We see this in humans with the flu, and recently covid, becoming more widespread when people spend time in enclosed spaces.
Yes, but only when there is a host already in the enclosed area, and a lack of removal of the virus that the host is spreading. 100 people crammed in a bedroom who do not have covid and have not been exposed to it aren't going to spread it.
In the real world, ventilation was so important because we did not know who may or may not be spreading the virus. If it's the guy next to you, massive amounts of ventilation would be a God-send. If no one in the building had it, then the massive amounts of ventilation could not reduce the risk of infection lower than the 0 it already was at.
So in our case, the virus has to be introduced some how. We don't know enough about viral infections in dragons to know much about what their cause is. It would be a safe assumption to state they come in from food we offer whether that be the insects or salad items. If this is the case, the virus isn't going to infect the dragon from hanging out in semi-stagnant air, it's going to infect the dragon through direct contact with the food.
they have evolved to subsist largely on morning dew in their natural habitat. This would mean the humidity must reach 100% in order for dew to form.
While I can't say I've seen any scientific studies to back this up, I would agree it's at least a plausible. But on that same note, like I mentioned earlier, respirations drop significantly while the dragon is sleeping. Especially so as the night grows colder. A dragon's metabolism and bodily functions come to almost a standstill in the cold of night. Less respirations per minute = less exposure to the humidity then one might first imagine. It's just a byproduct of being cold blooded. Without heat, the body slows to a crawl.
I'm going to go off a bit on a tangent here just because it's a valid point in the discussion of air flow - humidity. In my opinion and experience, humidity is a non-factor for our purposes. There are some here who like to preach that humidity can not get up above a certain level or your dragon will get sick. Those same will also say it can't get below a certain level. Truth of the matter is, to a healthy dragon, humidity does not matter. Obviously if you're misting your enclosure like a gecko terrarium, you're going to increase your chances for issues. But like you've pointed out, in the wild, dragons are exposed to a wide range of humidity levels. And in the wild, airflow doesn't play much a role in immediately changing the humidity like it would in our tanks.
So what's the take away? Humidity isn't the demon people think it is. Too low of humidity will not cause your dragon to have difficulty shedding. Too high will not give your dragon a URI. Extremes might worsen a URI, but they won't outright create it, usually.
The majority of URI's in our situation are viral, not bacterial. And most of those can even be traced back to improper husbandry and diet (too low of temps, improper/inconsistent diet being the main factors). In the hundreds of dragons I've ever raised (albeit many of them only as babies) I've only ever had one dragon get a RI. And it was because she aspirated water in her bath
. A man made situation that I put her in caused her illness.
Humidity and URI's almost need to be a whole separate thread entirely. It's a whole 'nother rabbit hole I could go down lol.
Presumably this would be less likely than in a mesh top where i would think the air movement would be mostly uniform.
I am by no means an expert in fluid dynamics. I wouldn't even call myself knowledgeable in it. However, I know that what has been recommended here has worked, and it's what I've done in the two dozen or so builds I've done over the years.
Lastly I wondered about possible benefits of air moving over the dragon itself.
I've wondered too. If anything, I think it could be more of an enrichment idea, much like some people put a dig box into the enclosure. Does a dig box help improve their health? Not really (ignoring gravid females who obviously need to lay)
. But it just adds to trying to fix the monotony of a living creature having to stare at the same 4 walls it's whole life.
If it could be implemented easily enough, and it doesn't effect the main important aspects of your husbandry, I don't see an issue with it, unless the fan was obnoxiously noisy, or caused vibrations throughout the enclosure. Does the possible benefits (even if they are unquantifiable benefits) outweigh the possible negatives that would come from implementing it?
I thought there was more to the subject of ventilation than what you laid out.
I am sure there is, and I welcome the discussion, from everyone. No one learns if people don't feel comfortable with questioning and putting their thoughts and opinions out there. Change requires discussion. But discussion won't always bring about a change.
It's only my opinion that the significant benefits of ventilation are for temperature regulation, and for there being a volume of fresh air to breath; that is definitely not a fact
In reality if those benefits exist at all, they may be outweighed by an inability to realize them without compromising the ability to keep temperature consistent.
Hmm, I should have read your whole response before starting to reply. It would appear you do understand that aphorism
In my opinion, questioning, learning, and experimenting, have always been one of the enjoyable parts of this hobby for me. If you can find a way to test your ideas on ventilation while not disturbing the key factors of husbandry, then I'm all for it.
It's late at night for me. Pardon the wall of text and pardon if anything comes off rude or like I'm brushing off your ideas. Not the intent here although things tend to read that way a lot when two people on the internet chat with eachother