Were Bottas and Massa pay drivers?
Also you are talking about Williams needing experience in the car but at the same time getting rid of Massa who is one of the most experienced drivers in F1. I'm not campaigning for Massa to stay just pointing out how the two contradict each other.
For what it's worth if Williams had the driver pairing of Stroll/Bottas this season like they intended to have I don't know whether any of what is being said here would have been relevant. Also I see no evidence of Hulkenberg as a team leader who develops a car.
Williams will be the same next season as they have been for most of the last season. Good at Austria and Silverstone, at the back at Hungary and Singapore, completely useless in the wet, and have a whole load of articles written about how they should be F1's 4th team.