I think you missed the parent's "+ other related tools". My company uses Jira plus Confluence plus Bitbucket, which are each more or less shitty, but they are more or less interlinked. And that interlinking does actually add value. It doesn't matter whether Jira is inherently better or worse than anything else. It doesn't matter whether an isolated Jira installation could be replaced with something else. The network effect keeps us locked in as well.