While PvP exp and Wolf Marks matter, a lot of us who play PvP also want achievements like the ADS mount, which we can only get with 1st place finishes. So while going 2nd, 2nd, 2nd, may seem just as good as going 1st, 2nd, 3rd, in actuality many of us don't feel that way.
I have noticed a large number of teams who seem to play for 2nd place. Maybe they think the 1st place team is too far ahead and 2nd is all they can aspire to at that point. However, I have seen comebacks from 100-700 when both of the teams who are behind work together to take points away from the 1st place team.
It is frustrating to be the team playing for 1st when one of the other teams is playing for 2nd. You leave the other team alone to go after the team in the lead and then the team you left alone snipes your node or otherwise starts harassing you. Then you only have 2 options:
1) Continue to go after the 1st place team and probably get 3rd, because you're essentially fighting 2 teams at once.
2) Leave the 1st place team alone and fight the other team for 2nd.
It's really a classic prisoner's dilemma type situation which is best answered by the Tit-for-Tat strategy. In other words, if you are team A and team B is in the lead, you have to go for team B, but if team C attacks you, then you have to punish them by retaliating against them rather than trying to press team B.
In that situation, team B will always win. The size of the lead for this to happen varies quite a bit, mostly dependent on the perceptions of the other 2 teams, but I really don't like playing for 2nd so I wanted to share my perspective with the community.
Sometimes stealing territory, even if it would be easy to do so, is bad overall strategy. It takes attention away from the team in the lead and forces other players to instead play for 2nd.
If you want to play for 1st, always focus the team in the lead. Only play for 2nd when the other trailing team refuses to cooperate.