Why are NFL hash marks closer than NCAA hash marks?

It's less about the kicker, and more about the defense v offense. Having the ball placed closer to the centre of the field means that the field is almost equally wide in both directions, making it more difficult to defend.

Further to this, the NFL moved the hashmarks closer together when they moved the posts to the back of the endzone, to help offset the increase in difficulty (extra 10 yards to every kick).

A big part of it is what was mentioned before - more touchdowns. IMHO it is also intended to create a more wide-open kind of play for fan consumption. To my way of thinking it's like a Butterball turkey. Most people want breast meat so they breed them to have lots of breast meat with the unintended consequence that the breast meat has hardly any taste. I don't buy the compensate for moving the goal post argument. NCAA kickers on average should be less able than NFL kickers but they manage to make field goals with the angle. It's just an additional way to cause more scoring and thus more excitement.

The NFL changed the speed of the game by moving hash marks in. It enabled the "sweep" to be run to either side of the field-- BALANCE was now a word used to describe offenses and not just 50/50 run pass-- as evidence was the vast number of 1000+ rushers (It was referred to as "the year of the runner") -- it also enables the crossing route or "east west game" which college does not have-- college is a slow power game that is a North South game, and has no east/west capability. The close hash marks allowed the "Mouse" Davis spread (run and shoot) to be installed-- it allowed Bill Walsh's 1-2-3 offense to be installed. It is the single biggest aspect to the leagues success via rule change, as it was both innovative and impactful.