re: Is tennis the most unforgiving sport if you're 3rd or 4th best?

There was basically an entire lost generation of tennis - players born in the 90s.

F1 has a similar problem due to the importance of money, engineering and construction. The sport attracted a lot of new fans and media interest during the excitement of the changing of the guards from Hamilton to Verstappen. But that was a rare exception - it's the least competitive sport. One team dominates and everybody else is just along for the paycheck and creating the illusion that there's a "race".