According to what I have seen Hornady doesn't seem to plan to stop making these rounds. If nothing else they are improving them and many more. Hopefully down the road others will want to match what Hornady is doing. Perhaps Reminton will in the future produce ie 450 marlin. I coud be wrong but time will tell as in the past what was not a good starter in the begining turned out to have a huge following years later.
I went looking for a 45-70 and found a .450 for about $200 less because it wouldn't sell. So far no problem finding ammo and I also reload. Many people can't think out of the box I guess. So the chicken little sky is falling feeling about the .450 Marlin has been a great opportunity that I capitalized on. Brass can be hard to find but not too bad. I guess if your stuck with depending on walmart to supply you with ammo it would be a concern. The independence of the reloaded makes the .450 a great buy because of the negative feelings you express.
My brass shortage is being filled with factory ammo that will get reloaded later. I haven't had any problem finding it. I just bought my 450 a month ago pretty much knowing that the rifle would no longer be produced by Marlin. I'm not concerned at all about ammo. Now I have a fine little collectable but I'll be shooting it.
Thats the way to do it gunner. Pretty soon you'll have a bunch(if not already). Thats how I did it and I have several hundred now counting the brass I found along the way. A little here and a little there adds up fast. A working collectable is the best kind, adds character if it is well cared for.
I'm not buying any Hornady Special Cartidge because the rifles are now made by Remington and who knows what they will do in the future after they ruined the old Marlin reputation and quality of the guns. I only look at older Marlins that came out of Conn.
Most of us are pretty independant, that being we are reloaders. I've collected enough components that I don't worry about running out in my lifetime. I've a 308MX and its my favorite rifle by quite a bit. I'm set with nearly innumerable bullets and 500 cases. I'm not worried. People like youself have been saying this forever since well before 2007 when I got my gun. Hornady developed the Leverevolution line not all at the same time, but inventing a new one when another older one has proven successful. I'm sure some more popular than others.