Hard to agree that teams should want the offensive mind and QB whisperer at HC when most of the last Super Bowl winning coaches came up as DCs, while a lot of their QB gurus won their Super Bowls as position coaches then bombed as HCs.
Haven't added them all up, but pretty sure there have been a lot more successful DC to HC transitions than OC to HC, even in the modern era only.
Are we really going to compare the Browns or a team in their situation to the much more stable Patriots, Ravens and Packers organizations?
Teams no longer let a young QB prospect like Aaron Rodgers or Steve McNair or Carson Palmer sit for a year or years anymore. If you are a bad team, and one who has been bad for a while, odds are you don't have a stable QB situation. If you get a nice young QB prospect, he's not going to sit very long, if at all, he's going to get thrown into the fire.
Given those conditions, in the modern game, in current times, what is going to help him transition better to the NFL? A head coach with an offensive pedigree and a history with QB1s or a defensive guy?
GMs no longer get the rope to transition through 2-3 head coaches and head coaches no longer get the rope to transition between 2-3 QB projects.
If you stabilize your QB1 situation, you can bring the rest of your team up to speed in some fashion.
If you try to stabilize your defense, two things can happen. It fails, in which case you have a much shakier road to stability for QB1 development and no defense. Or your defense is a wild success, in which case, you win just enough to not get in the range of the top picks where the best QB1 prospects go, and your only option is to gut future drafts to trade up or mine the journeyman circuit in free agency for a JAG. You've essentially created a treadmill team, one not good enough to contend, but never quite bad enough to get that critical high draft pick it needs.
The fastest road to stability for many of these long suffering franchises is to stabilize the QB1 position. Sorry, I think this just bears out in the basic eyeball test. And these long suffering and battered franchises like the Browns likely have a shorter window and higher pressure to succeed against the odds.