We beat Bolles in '99 at MBA. The return trip there in 2000 happened in a hurricane and should have been cancelled, but we went there anyways and got beat, and were later awarded the win because Bolles played ineligible players in the game. Hunter Hillenmeyer was on those teams and had a long career in the NFL. Those MBA teams from '98-'00 coached by Ricky Bowers could compete with anyone.
I don't think you necessarily *have* to have a D1 QB and WRs, but it certainly helps.
You need to be able to develop WRs. That's mostly about technique and coaching with the proper drills and reps in practice. There's a lot more to it than just putting some athletic kid out there and playing pitch and catch. Generally, while HS WRs are coached better now than they used to be 10-15 years ago, a lot of schools still don't do a good job of developing them.
As for QBs... you can throw a ton with a "pretty good" HS QB, but you need to play to his strengths and within his limits. A typical HS QB is not going to be dropping Hendon Hooker-style dimes 40 yards downfield to the opposite sideline. He's going to need to throw a bunch of high-percentage screens and safe dinks/dunks if you want to move the ball primarily through the air.
That gets a lot harder against the good teams you have to beat on the way to a championship. Personally, I'd rather play my best players at RB and QB so I can make sure they have the ball in their hands 20+ times in big games, rather than putting them at WR where they might be lucky to touch the ball 3-4 times.