The 45/70 has had a hundred year head start. It also has a plethora of available brass while the 444 has only a couple. It has nostalgia going for it.
Now, if you just go on performance, the 444 is right up there. The brass is heavier, more durable, less prone to dents and dings. There is a good selection of 444 cast and growing, but the 45/70 has tons so it is a catch up situation. Jacketed loads in the 444 are great performers, and flat shooting compared to the 45/70. I would just as soon have the 444 for most applications, especially on mid to lighter game. On bears, moose, and perhaps elk, the 45/70 begins to pick up points due to bullet weight. I also happen to find that the 444 is a very accurate round, with loads that go around 1 1/4 inch at 100yds and are full power.
I simply look at the cartridges as filling slots. Under 100 yards, under most situations, especially in thick cover, I use a 500. In good light, up to about 150 yards, moderate cover, I would use the 45/70 and iron sights. From 150 to 250 yards, or over 100 yards in poor light, I would use a 444.
There is the matter of throw weight also, the 444 is from 200 to 300 gr, the 45/70 is for 300 to 405 gr, and the 500 for 440 and up.
I would prefer a 444 to a 30/06 on most game up to 250 yards. SO, I dont think the folks here have any dislike for the 444 at all, but it IS the new kid on the block, and a lot of them have zero experience with the round. I think most of them , once they get to try one out, would find room on their rack for one.