Could it be the end for Yellowstone? Despite the fact new spinoffs are in the works, Kevin Costner reportedly doesn’t have high hopes for the future of the popular franchise after he made his exit in Yellowstone Season 5. “It would give him a lot of quiet satisfaction seeing those guys fall flat on their faces for even attempting to breathe fresh life into the show he sees very much as his baby — not theirs,” an insider spilled to a news outlet, referring to Costner’s reportedly tense relationship with producers and showrunner Taylor Sheridan. “At the end of the day, Kevin thinks the Yellowsto…