Why would they JIRA-ify it? They would lose their audience who sought a JIRA alternative in the first place. From their blog post on the subject https://blogs.atlassian.com/2017/01/atlassian-plus-trello/ they seem to acknowledge this
I happen to use, and like, both products. JIRA at work (where I want a lot of the features) and Trello for personal/small group projects and even family/household stuff where I just need _simple_