Disney COULD do more to make renting less attractive, but it wouldn't impact availability. People are going to use their points. If they aren't using them themselves and they can't rent, they'll sell their ownership to someone who will use their points. Since there are enough points for functionally full occupancy year round, the real question is "how fast does a given unit book at a given time of year." It doesn't matter if it is the dead calm of late January at Disney, or the busy holiday season, DVC will be booked - or pretty close to it - by the time of your vacation. As members gain experience, they learn that to make the most of their membership, they have to book early.
What Disney could do - they could make it impossible for non-members staying at a DVC resort to book the Dining Plan or MDE - and tie those benefits to membership (or staying with a reservation through Disney at a Disney hotel or DVC). They could make it known that members received "priority" on room requests and room ready (they don't currently) so that if you aren't a member, your chances of getting the coveted dumpster view go up or your chances of having to wait until after 6pm to check in go up. They could lower their own prices on hotel rooms or the benefits of hotel booking to make renting DVC less attractive But with DVC being their cash cow, I suspect they feel that renting is currently a plus for them - they get more people exposure to the savings and benefits of a DVC membership. More than a few members started as renters, and renters who are delighted are more likely to buy than ones that can't get the dining plan and have to wait until 6:30 to get a room that overlooks the dumpster.
As to runners (of anything from strolling through a 5k in an hour to running competitively for a full marathon), DVC is the perfect match for those that do Run Disney events as a repeat hobby - they make frequent trips, staying on site is important to them, they have a love of Disney (or they'd be running in their local events and not bothering to go to Disney). Run Disney events are crowded - they sell out. They can make Star Wars Weekend look like January at the Mall of America. While I would guess that a small percentage of DVC owners have ever done a Run Disney event, I'd bet that the number of Run Disney participants that owns DVC - and therefore disproportionately books those weekends, is a lot higher.
What Disney could do - they could make it impossible for non-members staying at a DVC resort to book the Dining Plan or MDE - and tie those benefits to membership (or staying with a reservation through Disney at a Disney hotel or DVC). They could make it known that members received "priority" on room requests and room ready (they don't currently) so that if you aren't a member, your chances of getting the coveted dumpster view go up or your chances of having to wait until after 6pm to check in go up. They could lower their own prices on hotel rooms or the benefits of hotel booking to make renting DVC less attractive But with DVC being their cash cow, I suspect they feel that renting is currently a plus for them - they get more people exposure to the savings and benefits of a DVC membership. More than a few members started as renters, and renters who are delighted are more likely to buy than ones that can't get the dining plan and have to wait until 6:30 to get a room that overlooks the dumpster.
As to runners (of anything from strolling through a 5k in an hour to running competitively for a full marathon), DVC is the perfect match for those that do Run Disney events as a repeat hobby - they make frequent trips, staying on site is important to them, they have a love of Disney (or they'd be running in their local events and not bothering to go to Disney). Run Disney events are crowded - they sell out. They can make Star Wars Weekend look like January at the Mall of America. While I would guess that a small percentage of DVC owners have ever done a Run Disney event, I'd bet that the number of Run Disney participants that owns DVC - and therefore disproportionately books those weekends, is a lot higher.