You actually just proved my point. Your example of the swing pass that went backwards was an extremely obvious, poorly executed play by the QB. Your point he is wasn't "experienced" enough to complete that play but that just limits your options. You also really do not know what the actual play call was. There were, most likely, other options on the play and the QB made a read, albeit a poor one and then compounded it with poor execution.I have to disagree with this. It is true if every play were executed perfectly, every play would result in a TD or long gain. But no play will ever be executed perfectly. A coach's play calling needs to put players in the position to succeed. Case in point, first play against Illinois last year. A freshman QB ( and I use that term loosely) is starting his second game against the worst rushing defense in the league. So the first play called is a weird swing pass that turns out to be a backward lateral fumble. Three plays and a little more than a minute into the game, NU is down 7-zip. Sure special teams are bad and the turnovers are bad and lapses on the defense are bad and penalties at horrible times are bad. But so is the play calling at times, which helps lead to losses. I don't call that an excuse, simply reality. In the above case how about a couple runs and if 3rd down a rollout run/pass option to help get Luke ease the beginning of game jitters?
I have done some small high school coaching and calling plays is difficult. You are correct in that most plays are not perfectly blocked. It might surprise you to know that some plays intentionally leave people unblocked with the idea of getting them in conflict thus taking themselves out of the play or rely on a back or QB to best them one on one. How many times have you seen a QB or RB break tackles behind the line of scrimmage or at it and make this great run for a big gain? A D can overload for a play and everyone can block well but still not have enough blockers to match the D. The play can still be executed well and not successful. In that case the D guessed correctly or were lucky.
The other piece you miss is asking if the swing pass or any other bad play was the actual call from a coach. Did the QB change the call based on what he saw, did he go pass on the RPO instead of running, or in some cases a play call is made and the QB can take it left or right, maybe he made a bad read.
Then there is always the weak link in a line. Why don't we run to the right more right at their freshman D line or whatever - well because maybe we don't have an OL on that side who can execute that block consistently.
You really should have a head set at even a higher level HS game and listen to what is said. The coach asks someone in the box what the D overall or certain players are doing, the coach makes a play call in a few seconds and that is passed to the team on the field and often the QB can go either direction or completely change the call.
I watched some UCF games during Frosts last year. I remember watching some outside zine plays go for long gains and TDs and hardly a single person was blocked. The D just made bad reads, took bad angles, or missed tackles or a combination.
I have called lots of terrible plays that netted zero yards and later called the same play that scores. Just saying the playing calling is a simplistic view of the game and ignores the complete process.