I've brought this up at my workplace as well and it isn't a budget issue in the US, it's mostly a lack of creativity or follow through from your office management team. Because more private, both in height and gap, doors aren't common in the US contractors aren't used to installing them and suppliers don't commonly carry them.

You can find them at suppliers in major cities but you have to rely on the persistence of your office managers to track them down and spend time on something that most people don't rally around or bring up in discussions. The compromise in my office was rubber strips that cover the gaps found in normal stall doors, those are easily bought and installed by anybody.