Its all pleated paper designed to goto a spec made by the manufacturer. Some large equipment runs a pre filter, some don't. I raced motorcross for years, so I know about oil air filters, and I also did filter testing on compressor pumps, and those oil filters are only good if you are keeping up with them, but they are honestly a waste, and your better off adding surface area to a paper filter if you need more flow.
You can't use random mods someone might do as a reason why an engine is a bad idea.
First I mentioned oem filters, then the wet filters, they were mentioned because people expect them to be better than dry filters, but even when you keep them oiled, they let in more particles than the oem, I agree with you, add more surface area and you will see much better improvements than a wet filter, heavy duty filters are more restrictive, and therefore filter better, than the oem filter you'll find on any production car, but they're so big they let through more flow
A turbo raptor from the factory would be much more trouble than it's worth, ford would not spend the money to create an offroad intake system for it, and ford wouldn't pay the extra few dollars per filter to put in a filter that cleans the air well enough to keep every dirt and dust particle out of the turbos
Diesel engines are built to last for millions of miles. if car manufacturers did that, they would go out of business faster than if their cars lasted 30,000, the heavy duty diesel engine manufacturers can get away with it because even if there's 20,000 engines that go without seeing a million miles in their owner's lifetime, there are hundreds of thousands of engines that see that many miles every year, or even every few months, whereas the majority of passenger cars and trucks see less than 30,000 miles a year
Since the majority of diesel engines cost the same new as our entire trucks do, a car manufacturer and diesel engine manufacturer have to sell the same amount (or more on the car manufacturer's side) of inventory per year to have the same amount of profit, therefore, since people use their cars alot less, they have to last alot less time for them to wear out at the same rate per year as diesel engines and the car manufacturer to stay in business
