When I was a child I dreamed of being a professional sportsperson - a soccer star or a tennis pro. Now in my late 20s, I shudder thinking of the pressure/stress, injuries and constant competitiveness that my life would have been if I had gone down that path.
You can be top 100 in Sweden and be a professional making good money. Being top 100 in Sweden is actually achievable. But in tennis you have top 128 in the world.
I don't think that's true these days, even defenders and the like need to perform very well for a team to be successful. There's a high level of performance and skill throughout the entire teams.
But there are simply more spots and to be top 128 in tennis is almost impossible.