Old timers usually had one rifle or shotgun for most of the work they needed to get done.
Reading up on how versatile something like the 45-70 or the 444 marlin can be will make some folks wonder if it is not a do it all sort of cartridge. They can be loaded with some round ball loads to be a bit like a shotgun, maybe something like a 410 perhaps. They obviously are well known for chucking one single big piece of lead out to long ranges if the owner of the rifle is capable then the round is usually capable. Folks have made low powered loads using filler to keep the gun powder back by the primer instead of the letting the small amount of powder for these loads get spread out and possably not burn right and cause a kaboom or inconsitant burns.
Sure something like the 44 mag or 45 colt can also do a lot of stuff as well.
And cowboy shooters have black powder loads for all of these since they are old designs and came from time before smokeless powder.
Lots of folks just figure a shotgun will do the job as well, and until you get into longer range stuff I agree with the shotgun. I honestly don't know how far out slugs can go, I limit myself to 100 yards for practice but I also tend to buy medium quality slugs. I know some of the better stuff is much more accurate, I just never tried it in my shotguns and have not read up to see what others feel it is capable of.
Overall it comes down to what you want to accomplish and if you can make the tool do the job.
To some extent the thread about 2 firearms for a year in the woods might have gone this direction if there was no limit on ammo.
Someone with a setup of lead, molds, knowledge, powder, books, primers, brass, and skill to use it all can make some rifles do anything they need done.
Some folks would do as well to just have a gun for each job.
Think about it, buy it and see what you can do with it.
There is an article I have a copy of somewhere about oddball loads for the 444marlin but if you run some searches you will run across similar stuff for other calibers. I just got to where I liked the 44 mag and the 444marlin is a bit like a longer 44 mag round. So some of the bullets could be shared perhaps, but to some extent you might be trying to run really light stuff in the 444 doing that so it might not be best to try to go that route.
I have owned 2 different 44 mag marlins. Eventually sold them both. They are handy little things but I prefer a revolver since I can wear it all the time and for a rifle I would rather have a rifle cartridge. The one thing that gets me to reconsider this is a 44 mag rifle set up with a can on it.
The round for long term survival is the one you know, stocked ammo and components for, and can use to do what you need done.
Expecting a 44 mag to do what a 444 marlin can do is a bit much. Using regular 444 marlin loads for everything will use up a lot of powder compared to what some 44 specials out of the marlin 44 mag lever action might be able to do just fine. Get to where you download that 444 marlin and can safely operate it at lower powder levels, and you might have something.
I don't have the skill yet.