Objectively that may well be true, however if you hire someone more experienced than you then perhaps they should be supervising you and not the other way around.
Also I think most geeks like to think of themselves as Jedi Masters. There is also the fear of someone tearing you a new one for the quality of your codebase.
I'd like to think in an ideal world we only ever hire colleagues, and our teams are, for the most part, meritocracies without hierarchy. Technical Leads guide development and mentor those less experienced, instead of directing it and passing down tasks. Management should be isolated from the team you work with daily, and should be there only to help long term progress (and other hands off management things).
Working with closely on a day to day basis with someone up the management chain from you is miserable.
Working with closely on a day to day basis with someone up the technical competence / experience scale from you is fantastic.
Also I think most geeks like to think of themselves as Jedi Masters. There is also the fear of someone tearing you a new one for the quality of your codebase.