I always felt the reason for drafting Hooker was different:
1) The team, including Holmes and Campbell, said right from the very start that they were fully behind Goff and believed that he was THE Lions QB.
2) That's never changed, and based on that, and knowing where starting QB AAV's were headed:
3) How much do you want to spend on a backup QB? $5 mill per year? $10 mill? More? Two of them, if needed?
4) THAT is a huge reason to take a chance on drafting a QB: not as a threat to Goff, but because of... money.
5) ALSO: they believed they were heading towards Super Bowl contention on an annual basis which means, IMO... the team had BETTER have a quality #2 QB to salvage a season or playoffs if Goff got nicked up for a few games. While Hooker was injured or on his learning curve that meant Teddy Bridgewater.
My Summary: The team WANTS Hooker to step into the #2. They WANT him to show himself fully capable as a Bridgewater or a Goff-lite (IIRC, his draft comp was Goff...?). They WANT him on a cheap rookie contract. Or even a cheap second contract, as long as he proves himself worthy.
Holmes took a risk with Hooker that he could get this. He didn't care if Hooker was older, injured, or a career backup to Goff. There was the possibility that Hooker could turn into a Bridgewater or Goff-lite... enough to be a dependable #2 QB on a Super Bowl level team.
He may never get there. He might. they are PUSHING him hard to improve and get to that level.
But THAT's the risky reasons Holmes made that pick.
It had NOTHING to do with Goffs' "perceived" questionable status on this team. They NEVER waivered (Holmes & Campbell) in their support of Goff.
IMO.