"Lisa, I'd like to buy your rock."
No you didn't. It's disconcerting that you feel you have some deeper understanding of how positioning is applied to defending. I hate to burst your bubble, but it really isn't that difficult of a concept.
No amount of positioning will entirely remove the advantage of pace, hence why we've used this example, where Vardy has the space to run into, was in a similar starting position to Lindelof, and yet Lindelof still managed to keep up. If Lindelof was slow then that simple wouldn't happen, regardless of position. That doesn't make Lindelof lightning quick, but it means, without contestation, that he isn't slow either. I can't believe I'm having to explain this in this much detail. But hey, there was that one time with Carrick, right?