Re: Chance that the Williams sisters will retire if they lose the Wimby title?
POSSIBLY Venus. I think she knows this is "shit or bust" time. She's not getting any younger, her mental strength is deteriating every year, and her body is starting to break down, hence the recent flood of injuries. She knows Wimbledon is her only shot at a Slam, and she also knows there's no guarantee she'll get another chance next year. I actually really get the sense she could've played RG, but she chose not to because she really wanted to go all-out for Wimbledon (hence why she looked so much sharper than Serena this week).
Serena's completely different though. I don't think she'll have the same sense of urgency. She's been pretty healthy physically for the last few years after finally starting to take her fitness seriously (obviously the foot injury was a freak injury, unlike Venus's injuries that were caused by gradual wear and tear), and I think she'll be confident she can keep going for a few years yet.