Running to the outside is a great plan if you have the faster player. In Pop Warner, you can just give it to the fastest kid and let him run around the end. Nobody's gonna catch him.
However as you get farther up the ladder it gets harder and harder to get to that edge. In college, you really need a WR to make a block out there and try to free a back or receiver to run around the edge.
In the pros even the linebackers are fast enough to beat a back to the edge unless he is lightning fast.
Part of the theory behind the spread offense is that is spreads out the defenders, creating lots of one-on-one matchups where a quick offensive player can make a defender miss, then have open field ahead of him.
If a defense is spread all across the field and a back can slip through a hole in the D-Line, he should only have to beat a LB or a safety to take it to the house.
The thinking with Holloway may be that if that one guy misses him, he gone. Unfortunately, it doesn't take much to knock him down, so that hasn't worked out too well.
A good example though is Dak Prescott. Two years ago, we would spread out a defense so when Dak broke through the line he only had one man to beat. In his famous run against LSU he beat a safety and made him look silly.
The next year, LSU left their LB Beckwith in the middle shadowing Dak and he wasn't able to beat him very often.
My favorite plays are when a back breaks through the line in the middle, makes one cut, and takes it to the house. That's how it's supposed to work.