There is an awful lot of 30-30 ammunition going must slower than most people realize. The original load was for a 160gr bullet at 1970 fps IIRC. I've clocked plenty of factory 30-30 that is sub 2000 FPS from the muzzle. Even if we use the optimistic factory specs on lots of 150 gr 30-30 ammunition, it's dropped to 2000 fps before it gets to 100 yards, and 170gr ammo starts at 2200 fps...Although reality is they factory specs are probably fudged. And lots of 30-30 bullets end up looking like yours and found on the offside, so that's why I noted the similarity.
This is a study that's been posted before on CGN. While it has to do with shooting humans and incapacitating/killing them, it does show that for the most part, they all work about the same.
https://www.buckeyefirearms.org/alternate-look-handgun-stopping-power
When talking about handgun cartridges for hunting or defense I had always subscribed more closely to Elmer Keith's big, slow and heavy thoughts. I felt that as the handgun was going to be much slower than a rifle, the way to compensate for it would be to make the bullet larger in diameter and weight. But this study as well as a few other things (including Shoemakers 9mm grizzly) made me rethink a few things. My ideal wilderness carry handgun was originally a 45 ACP loaded with 45-08 cartridges that produced similar numbers to a 44 magnum, but had 10 rounds and was faster to reload than a 6 shot revolver. Power, capacity, fast reloads and better ergonomics than a revolver. And for a human defense carry (not applicable in Canada but it's part of the whoel concept) it would be loaded with 45 ACP, because a 45 ACP is twice the weight of a 9mm and kills better, right? Well, not according to that study. And since most handgun rounds are fairly equal, as you note, then it comes down to where you put the bullet. There is no question the 9mm can be shot accurately faster than a 45 ACP, 44 Magnum, 38 Special, whatever.
Couldn't agree more with the 45-70. When the 45-70 resurgence started a few years (decades?) ago I thought wouldn't it be cool to get a 45-70 Marlin and load it with hard cast and have a real thumper. But then I started shooting some and looked at the ballistics and didn't see what all the fuss was about. Even with hot handloads it comes up short compared to many modern cartridges. And a M94 carbine in 44 Magnum or 45 Colt would work just as well yet be lighter and nicer to carry.
I think if I was allowed to carry a handgun for wilderness defense, these days I would take a Glock 9mm. While Glocks are not my favorite handguns, they are light and work well enough. I can make 10 good hits with a 9mm and reload with a fresh magazine, faster than emptying the 45 ACP with good hits, and certainly faster than shooting a 44 magnum revolver. And almost anyone can shoot a 9mm accurately with a bit of practice, the bigger guns take much more effort. To defend yourself from a bear you need to hit it well, preferably in the head and a 9mm can give you the ability to make very fast accurate hits. At the very least even without a brain shot, it is probable that a bear getting hit in and around the face will break off the charge.
Considering how fast and accurate a good 9mm PCC can be shot especially with a red dot and how handy some of them are to carry, I can see their usefulness in wilderness defense although a rifle is still a better option when going into areas I expect to see a grizzly.