If you look at the current top 3, Arteta was hired having never even worked as a manager before. Slot had never managed in a top league. Maresca had one good season in the Championship.
This snootiness over both the background of both players and managers is silly. There are no rigid rules of selection that will guarantee you get the right manager. Lots of inexperienced or obscure managers have done well at the top level. Lots haven't. Ditto for the more established "elite" names.
Pochettino was the 2014 equivalent of Iraola but he turned out to be the best manager we had for decades. I'm not saying Iraola is the guy but you should analyse the qualities of the individual rather than the club that currently employs them. Their vision of football, their personality, their communication skills, etc. You can't just sneer at a manager because they manage Brentford. Who could have done a better job than Frank with that Brentford squad?