There are other considerations too about fly design. I agree that many large predators engulf their prey, or like those in the Pike family tend to grab & hold on using those big teeth. Bluefish & sharks as has been mentioned are biters, using their sharp teeth to bite thru flesh, which both disables their prey & is how they eat. However, flies tied on long shank hooks can have problems with leverage. The shorter hooks reduces that leverage the fish has against the hook when an angler is fighting them. Plus long shanks can be prone to fouling of the materials around the hook, depending on the materials being used.Tandem hooks can create fouling problems too, and can be more difficult to cast. Tandem hooks were used on many of the Rangeley/Carrie Stevens type streamers, but they were primarily trolling flies, so they were not cast. Tandem hooks are used with some big Billfish flies, but the casts are often very short, literally right behind the boat after the fish has been teased within range . Also Billfish flies may not necessarily be long in dimension, but are bulky, creating an illusion of size. I've got some "Billfish" poppers that are no larger than those I've used for LM bass, but are more bulky. ( I use such poppers for Striped Bass too.)
That last fly shown, the red & yellow one is typical of many of the flies used for Striped Bass, and the shorter shank hook allows the most movement of the materials & least amount of fouling issues, yet hook up's are not a problem, provided the fish is trying to eat the fly. Sometimes, they will strike a fly, or prey but may not be attempting to eat it. Perhaps it's a territorial thing, or perhaps another reason, but they don't always strike simply to eat. They may also be striking to stun, which also does happen. I've had them strike at flies & lures, assuming their trying to disable the prey & strike again to eat the fly or lure.
Specific fish species being targeted should be considered, as should the size of those species. A large Striped Bass, 30" long or bigger can easily swallow a 12" or 14" prey, so swallowing most flies, even those close to those dimensions is not an issue. However, a 24" Striper, even though they might attempt to strike such large prey, may not really be able to easily engulf it, but prey in the 5, 6 or 8" size range they would have no problem eating.
Over the years I've caught both SM & LM bass while targeting Striped bass or vice versa where they hit flies or lures almost as big as they were. I once hooked a SM bass of about 6" long on an 8" long saltwater type pencil popper. That may or may not be an attempt at eating, but might also be some other reason for the strike. I've caught plenty of average size (2-3lb) SM & LM bass on bigger flies (8", 10") that might not normally be used for that size bass, yet they got hooked, inside their mouths on a short shank hook, tied at the front of the fly. IMO, this indicates they were trying to eat the flies. If I was specifically targeting that size bass, I would not often use a fly that big, but more in the 3 to 6" range. I've also hooked plenty of fish of various species outside the mouth & even in the body sometimes. When predators strike at prey they are not always successful & even their attempts at flies or lures may not be perfect, so they end up hooked in less than ideal parts of their body. I've found this to be true more so when the size of the fish is generally small compared to the size of the flies or lures being used. It's their aggressive nature to strike I guess regardless of whether they can actually get the fly or lure in their mouths.
I would expect, based on some of the flies popular today, that larger trouts or salmons could swallow relatively large flies. (Galloup's flies are good examples) yet many have a hook at the tail end instead of at the front end. Perhaps that's not necessary, or perhaps it's more the result of smaller size fish striking at the bigger flies with more misses than hook-up's and those styles have evolved to solve a hook-up issue with those species. I can't say for sure as I don't fish for the trouts very often. Just a guess!