I was writing this post when you replied. Might be more you want to reply to in it...
No one is saying Sansa didn't get a win, she killed Littlefinger. That's a win. But that's not what my point or original reply was to.
As far as the Boltons, Littlefinger had to still be seen as friend of the crown. Which is to say he couldn't openly support Sansa in the North. This is why he setup the deal with Roose Bolton to side with Tywin so Littlefinger had someone he could support in the North and not seem a traitor to Tywin/Cersei. Hence the Red Wedding. Once that happened, Littlefinger left for the Vale with Sansa, married her to his ally in the North, the Boltons, allowing him to still seem a friend to the crown but secretly plotting to take the North from the Tywin/Cersei. Him working with Roose now seems necessary to the crown instead of betraying it. He USED the Boltons and installed them in Winterfell as a place holder until he could operate freely because he had not yet secured himself as Lord of the Vale. Once he did, the table was set. He was going to kill the Boltons. Using his relationship with Cat, Robyn and saving Sansa was what he was banking on for Northern support. He didn't need to marry Sansa to have their support for anything anymore until Jon was named King in the North.