Newcastle did it with Shearer expecting that big uplift in fortune and got relegated.
I'm not saying we should go for Unsworth or not, but that comparison is wrong on so many levels that it hurts.
Newcastle were all but relegated when they appointed Shearer, who had never managed a team at any age group or level, had no coaching qualifications, and had no knowledge of the club or the players.
Why not bring up Guardiola or Tuchel as examples, both fully qualified coaches promoted from within the club's youth setup with zero senior experience and did alright. You can also cite cases where it went wrong like Ricky Sbragia, but the Shearer comparison is just lazy and invalid.
(Though if the alternative is Sam Fucking Allardyce, we might as well not bother and leave Koeman do his thing.)