I'm not convinced Renault-Nissan have the stomach to continue in F1.
Carlos Ghosn (Renault Group CEO) has had to make key cost cutting decisions to pave the way to Renault profit. Nissan at the moment is keeping the group in the black, just. Renault however, is like a lead weight. Plus as an image boosting exercise, F1 doesn't have the halo factor it once had.
On track, the Renault engined RedBull have at least one title contending driver. Where are the Renault works team? Nowhere at the front, well not consistently. Redbull have 104.5 points (2nd) where Renault are 8th out of 10 with just 16 points.
The Formula Renault series' are going well, the racing Meganes are too.
Then you have the new Piquet-gate story. Not what you want from an image point of view; the Renault brand dragged though the courts by Flavio et al.
If you had a business decision to make; cost cutting in your motorsport division, what would you do?
Renault have a long line of success as an engine maker but will it again as a constructor? Flavio has enough to buy out the Renault stake in the team. Renault could continue with RedBull and TeamFlavio as suppliers can still claim an active part of the F1 circus without the negative headlines as a constructor.
Remember Renault (and BMW) only became a constructor during the time when F1 was going that way 8+ years ago because it would have been advantageous from a technology point of view. F1 isn't still moving that way. With a return to garage teams with off the shelf engines; look at how BrawnGP (Mercedes powered), RedBull and now Force India (Mercedes again) are at the front.
The new rules mean the added cost as a constructor making it's own engines isn't the way to get trophies anymore. BMW know it, Carlos knows it, it's just a matter of when and not if.
Maybe as a owning team principle, Flavio will focus on wining on the track and not in the courts.