The whole reasoning behind this behavior, in case you're wondering, is that "environment" variables are supposed to describe the environment that scripts and applications run in. This means that typically they're set at a level higher than the process (e.g. the shell, describing the login/shell session, or the web server, describing this web transaction).

Items specific to an application or set of applications might better be placed in a configuration file, especially if they're going to be relatively static.