re: The other issue, "Prevent Defense"

This isn't a unique problem to LSU. It's innate to the game of football. Assuming even talent, an offense that has a reasonably good passing game typically can march down the field on a defense when they play with a 2-minute-drill mindset. What you're seeing is playcalling optimized: no inefficient running plays, and passing plays called to be as high-% as possible because there's no margin for error. In most cases where a defense beats an evenly-matched offense, it's because the offense is calling plays inefficiently.

There's a pretty simple way to see how this is innate to the game. The fact that we even acknowledge "prevent defense" or "end of game drives" as unique entities separate from the rest of the game should say something about the phenomenon I'm talking about here. If end-of-game drives weren't any different from regular drives, why is it that we talk about them as being different? Why do several teams (LSU included) play great defense all game and then mysteriously collapse at the end?

Instead of reducing it to an arbitrary "clutch" factor that, evenly applied, doesn't make sense (why is a team not "clutch" for playing great defense for 58 minutes out of 60?), let's look at the underlying dynamic of end-of-game drives. EOG drives are optimized for gaining the largest amount of yards in the shortest amount of time, it's no surprise that a team should struggle with them the most.