It's complicated, but the sentiment that charging your most price insensitive people a fixed price is nutty is still true - I don't think that's wrong. Although Jira has a fixed price ceiling, Confluence is not priced that way: http://www.atlassian.com/software/confluence/pricing/?tab=do...

As for FogBugz, as another poster wrote "if your competitor is an order of magnitude cheaper, and not significantly worse" you have to respond to that (even if you think they are nutty, and a bit more than significantly worse).