Wide running lanes are what's supposed to happen when the play is blocked well and designed well. If the defense has shown a tendency and the OC sees it and calls a specific running play and it's executed, boom! The fact that it doesn't happen all that often tells you that it's a perfect storm when all of those things happen at once. Oftentimes the defense doesn't show an obvious tendency. Oftentimes the play call isn't just right. Oftentimes one guy misses his block.
What I hated most as an OL was when I was pulling, the guy next to me getting pushed back - retarding my progress and the play as a whole.
When you see a DL or LB come through scot-free and kill the QB, that can be any number of things. Sure, the QB could have audibled and a guy missed it, but that's not often the case. It's usually more about the DC finding a chink in the OL's blocking scheme and purposely exploiting it. Or even a tendency of a specific guy can lead to that as well.
Say you're a DC and you want to blitz through the B-gap between the guard and the tackle. If you blitz your inside LB straight through, either the OL will pick it up easily or due to their scheme, a RB will fill that hole. But on film, you notice that on a delayed blitz, that guard in particular, when he has no one to block initially, always turns in and double-teams whoever the center is blocking. That is useful information. Now you can plan to loop your outside LB towards the interior of the line, getting there a second or two later (on purpose), and that guard doesn't see him and has turned away from him. He gets through cleanly because the RB only has the assignment to block the inside LB on a blitz. Now honestly, if you can believe it, whoever is supposed to block that outside LB (if anyone - not everyone is accounted for on every play, by design)should be yelling during the play that his guy (the OLB) is blitzing inside.
It can get frustrating if you're playing guard and no one is lined up on you, no one blitzes immediately, you get a great chip on the nose tackle, knocking him over, but seeing your QB on his back because the OLB got through your area and your TE didn't yell a warning during the play.
Crap like that is why some coaches sleep in their offices, playing out all the what ifs....there aren't many in HS, some more in college, and plenty in the NFL.