The best shots of anchoring a hog will involve the CNS. The brain may be fairly small, but it can be fairly easily damaged by hydrostatic shot. That is why shots behind the ear that don't actually hit the skull or the neck vertebrae will often drop a hog as will shots through the sinuses or even shots that don't penetrate the skull fully. The nice thing about rifle neck shots behind the ear, if close enough to the spine, will involve the upper spine or lower brain via hydrostatic shock, rupturing capillaries and otherwise producing significant CNS disruption.
Note that the location of the ear is at the rear of the skull. Too high behind the ear and you simply clip soft tissue and the hog runs off. If you draw a 1" half circle from forward of the base of the ear, down around and behind and hit within than half circle or slightly above, the desired effect will most often be attained. This assumes the hog is in a nose forward position, not nose down. Note that the base of the ear is where the proverbial "ear hole" (external auditory meatus) is located that many hunters attempt to hit.
Keeping in mind that pigs are 3D where you hit relative to the ear hole matters. If you are shooting from a lateral position and are 1-2" high, your shot may go through the fleshy ear (pinna) and pass over the top of the skull. Ifyou are firing downward from a lateral position, a slightly high shot on the ear hole may drill a hole downward through the top of the skull.
Remember that it isn't just shot placement, but the trajectory of the bullet through the animal and penetration. A couple of weeks ago, a fellow I know placed a .308 round right behind the front leg of a pig quartering away for what should have been a nice heart or lung shot (or both given the downward trajectory). However, the round impacted the humerus and apparently deflected out of the body, failing to involve the vitals. Shot placement was excellent, but the trajectory aspect failed and as a result penetration was through non-vital tissue. This is what Lost Sheep is referring to about no magic spot ON the hog but IN the hog.
The brain is also surrounded by a lot of very hard and thick bone.
No, it is not. The only particularly thick bone is at the top rear of the head and that is because of muscle attachment to help keep the head elevated. Otherwise, the brain is surrounded by two thin layers of bone, usually no more than about 1/8" thick each, but gapped quite a bit by cavities, primarily marrow/sinus-related.
The bone of a pig's skull is not particularly hard either.
There is nothing significantly different about a pig's cranial bone composition than that of other animals except for the gap between the inner and outer table that might be more akin to what you see in other animals that expect cranial impacts. The thin outer layer can be damaged without harming the inner layer and there is a bit of padding between the two.
Otherwise, the amount of bone in a pig's skull protecting the brain is actually less in many cases than than which you would find in a human skull in terms of actual quantity/thickness of the bone material itself.
The article is useful, but the folks over at Texas Boars also have some very strange notions. At the following link, they will also tell you that only hybrid wild boar will have a special tooth. That is complete hogwash.
See post 45 here...
Basically, the specific tooth isn't anything other than a vestigial premolar found in domestic, feral, and eurasian hogs. It is not unique to being a hybrid hog.