As an active phpBB and Invision user for years, I recall voting being only available with plugins, and they weren't typically considered upvotes or downvotes but reputation votes for the user. May sound like six of one / half-dozen of the other, but it was still a very different environment.

In addition, bumping was more of a way to get attention to something than to vote. As when asking for help on a specific topic, or to let other users know you edited and added to a thread's initial post.