Michael Andretti - Signed by Mclaren in 1993 to appease Marlboro who needed to a world champion driver as Senna was thinking of a sabbatical , Prost had joined Williams and Mansell retired. Ron left very little options signed Andretti who was an Indycar champion and also help appeal to North American market
Lets say the relationship was nothing short of a disaster for Michael who failed to live up to his Dad's reputation in F1... refusing to relocated to Europe and do winter testing and was commuting to races from his home and not with the team . He got reprimanded by Ron for qualifying 6th in Brazil and as he toiled through the season there was slow improvements. His last race was a podium at Monza - the Italian GP - the country of his ancestors and he quit after that fed up with the environment
-2007 - having not competed a full season for more than 6 years - he was surprise choice by Williams to partner Rosberg for 2007 owing to the fact that he was excellent with his technical feedback at MClaren where he had 1 outing in 2005. It showed the lack of racing where he was off Rosberg's pace and struggling to adapt to Bridgestone tyres and usually was about at least 5 places. Some crafty drives at Monaco and Montreal showed his experience but seeing that his career was not getting anywhere and Williams have Nakajima to please the engine suppliers he retired
- impressive showings in a March where he lead races and challenged Ferrari and Mclaren bought him a dream drive at Ferrari in 1992. Unfortunately the political experience left him shell shocked and battered as the team was going through a transition period and he was never able to match Alesi's pace who was the team leader. The pressure of being an Italian driver did not help either and he was sacked in 1992. A lifeline at Jordan might have rejuvenated his career in a familar small team environment but unfortunately this never happened which included failing to qualify for Brazil. He left in 1993 to replaced by Thierry Boutsen (see below) a broken man by his Ferrari experience
Made way for Mansell in 1991 by signing for Ligier which became two years of hell given the atmosphere within the team who ever under delivering despite having the 4th biggest budget on the grid. Helped the team secure Renault engines in 1992 and replaced Capelli in 1993 but was too tall and race rusty and got absolutely destroyed by Barrichello forcing him to retire from the sport after Belgium GP
No one's fall from grace was as fast as Jacques Villeuneuve in 2003. 6 Years after winning the drivers title in his 2nd season at Williams but unable to defend it in 1998. He thought he could build his own superteam like Michael Schumacher at BAR with Craig Pollock which proved to be more challenging especially when you don't want to listen to your engineers and you got people who really put their mouths in it by making big claims before the car turned a wheel.
His status as No 1 was threatened once BAT hired Dave Richards to replace Pollock who immediately signed Button and his two fingered response to the team for trying to make him take a pay cut did not help either. Seeing Button as a threat the results were not coming due to strategies not materialising in races because of reliability issues whilst Button kept scoring points. More involvement from Honda wanting to promote Sato backed him into a corner and forced him to quit in 2003
Which drivers were being invited to quit ? None of them was supposedly pointed a gun to their head except maybe Montoya felt that way
Capelli - retired 1993
Boutsen - retired 1993
Villeneuve - pretty much quit in 2003 because he bought about his downfall and he did not want to compete the last 3 races knowing full well he may not have seat in 2004
Wurz - he knew his time was up as well
Andretti - quit because he really did not like being in F1 and felt Mclaren environment was not for him
Can't remember any individual names but I remember reading of several drivers deciding to retire from motor racing following the Le Mans disaster in 1955, although one or two of them made a comeback sometime later.