I really want to see a Jira competitor succeed, it's healthy to have some competition. But it's hard to find something that competes on the per-user price of Jira Software On-Premise. (Jira Cloud is a different story...too many reports of slowness, too many UI/UX changes, too many powerful add-ons do not work on Cloud).

Next, you have to be the system of record for a company. To do that, everyone needs a license. Jira has a foot-hold because it is used for developers and for every other facet of a business (basically all company ticketing).

Although Jira sacrificed ease-of-use by offering customization, it's also what allows orgs to skip buying other tools.