I would think that, no matter how hard a company tries to hire people of the same mindset, temporary hierarchies would develop - not necessarily along the lines

I would think that, no matter how hard a company tries to hire people of the same mindset, temporary hierarchies would develop - not necessarily along the lines of seniority, but along the lines of who had more experience/comfort/knowledge of best practices, etc. regarding a particular domain, technology, etc. Ideally, the hierarchy would be truly temporary and whatever knowledge/experience/insight caused one person to become the project "shepherd" would be willingly shared amongst the other folks.