The big ones, including the .44 Mag simply aren't for everyone. I well remember the days when it was very common to find a used .44 Mag in the used shelf, along with a box of ammo with 44 unfired rounds and 6 empties.
That's a good point, and still valid today.
Even the "lowly" .44 Mag still suffers from the same 'wishful thinking' of some buyers.
For example: Right now, there's an essentially brand-new .44 Vaquero in the display case of my preferred LGS. Next to it, three empty cases -- because that's all the buyer fired before deciding that they couldn't handle it.
I think it's still just as prevalent in the rifle world, too.
There are countless .45-70s, .444 Marlins, and Handi-Rifles and Rossi single-shots in nearly any intermediate to 'high-power' chambering that have just a few rounds through them.
And I still see .458 WMs, .338 WMs, various WSMs, and some of the RUMs, RSAUMs, and RCMs show up with less ammo fired than is necessary to even sight in a scope.
I have one, myself, that actually suffered a double dose of big bore anxiety.
A guy wanted one of these super-awesome .444 Marlins that he had heard so much about. His brother bought a Marlin 444 for him as a birthday gift in 2007. One round was fired, and he didn't like it. He went back to his .308 bolt gun.
The 444 sat in the closet until 2016, when it was given to the man's son.
The son took one look at the "giant bullet" and put the rifle up for sale at a surprisingly low price, because he figured most people would also be afraid of such a 'big' rifle.