The requests to to turn it into a generic booking solution were merely self-interested. You are an experienced developer working with a team, with (presumably) a bit of commercial motivation and funding. Those of us working on the more specialist (or less profitable?) use cases, with less knowledge of Drupal, less time, and fewer resources, are bound to check whether we can just adapt an already developed and tested module.
Fortunately this is open source software, so those developing other modules can make good use of your source code.
I expect solutions that have very tiny units and booking periods (e.g. renting a tennis racquet for an hour and a half) will have significant UI problems. There is not really much comparison with hotel rooms.