In my opinion, lot of people on /r/nba believe that winning a championship in 2012 will make a difference in 2016 when a player decides his future with a team. This makes little sense to me. However, I do think that the performances of 2015 and especially 2016 will influence a decision in 2016. This season is not going well at all. If things continue this way, it will definitely influence KD's decision for his future negatively. This season and the next two I think are the most important. If the Thunder are ever going to be aggressive and pay the tax, this summer makes a lot of sense.
I think there is a lot of speculation in the media about players going to large markets from small markets. We hear way too much about terrible teams like the Lakers and Knicks compared to the Atlanta Hawks of the league. There is about 20 million people in both the metropolitan areas of NYC and LA, which is about 6 times larger than the state of Oklahoma. The media speculates about Westbrook leaving OKC for Lakers, because what else are the Lakers going to discuss with their vast audience? Nobody currently wants to play with the Lakers. That's why they lost Dwight Howard and Pau Gasol. They discuss Westbrook and Love teaming up in 2017 because they played one whole year together at UCLA. It's a silly to even discuss what FA moves are going to occur in 2017 and this has been going on for years already. And this team literally has no core whatsoever.
Fans are incredibly biased. They are a very easily manipulated group of people that will believe whatever optimistic proposal regardless of how ridiculous. When the Knicks traded Shumpert and Smith recently it was reported that they were able to steal Reggie Jackson, and every ass-hat believed it. Then when it was revealed that all they received was Lance Thomas and a couple of other players they waived ESPN rated their trade as an "A" and everybody's happy. The Thunder received a "D" for trading a +19 first round pick for a #4 pick in 2012. Every move the Thunder make is highly criticized. Trading Harden was apparently the worst move in NBA history, but letting Dwight Howard walk for absolutely nothing was a very savvy move.
TL/DR - There is definitely some logic that if the Thunder are unsuccessful that their stars will leave. That being said, the media has been discussing these possibilities for years because it entices an easily manipulated large audience.