Allegedly the ending was forced up the show...
I am unconvinced.
As I said a few weeks ago, the Showtime head has had been pushing for a spin-off for a year and I posted at the time whether that may've factored into the final scene.
Is it convenient given how the finale was been received, sure, but it isn't to me a totally unbelievable claim given Showtime's head director viewpoint has been public for months, especially if there were incentives for Buck if he played the game - the development deal he earlier in the year.
Having said all that, even if an ending was forced on them it doesn't take away from the steaming heap of gelatinous whale vomit that was everything leading up to the finale.