Yep, I firmly believe one of the reasons Cape buffalo acquired such a reputation for being hard to kill is the widespread use of solids (especially in the .375 H&H) before so many controlled-expansion "softs" appeared on the market.
Probably part of it, elephant bullets aren't a good match for buffalo. To build on the idea a bit, much of the reputation of African plains game for being harder to kill is because people are determined to use their buffalo bullets on animals the size of a well fed whitetail or mulie.
Hard bullets need hard targets just as much as hard targets need hard bullets.
