Of the 5 dysfunctions, none is more important than the last one. I don't care what team you're a part of - or leading - if you're not achieving results as a team then there's no point to your team existing.
At the end of the day, teams are formed for a reason. There's an objective or a project for every team and the ultimate of the 5 dysfunctions to overcome is results. Look at an unhealthy team and rather than results you'll see individual egos doing their own thing due to a lack of vulnerability, conflict, commitment and accountability.
The opposite is true for healthy teams. 5 dysfunctions can all be overcome. It's not easy, but it is possible. Give it a go and watch your team move from individual effort to team combined goals that achieve the results your team exists to achieve.