For the record, many of the bigger animals like Elephant, hippo, rhino are killed or shot with both Solids and softs. in many cases multiple times.
One reason I use the Barnes X bullets in my 458Lott is that they are like a semi expanding solid bullet. They seem to bridge the gap between the soft and the solids.
Buffalo are nearly always shot with softs and when I was working in Alaska all Brown bears were shot with softs too. The only three aniamls I have know to really be better off shot with solids are the hippo, white rhino, and elephant. I have a soft here From my rifle that I took out of a single shot elephant kill. So the softs will absolutely do the job when the aim is true. This particular cow had it's trunk wrapped in wire and had pulled about the last third of it off. It was angry and sick. It was shot in the head and dropped at the shot.