Money.

  A career in pro badminton can be incredibly rewarding. The pros I know very well have amazing experiences in other countries playing these great international tournaments. But they face a constant struggle. They must fund the dream somehow. And since the only 'certain' sponsorships they will get are from badminton companies themselves,  they end up barely making ends meet. You simply can not have a full time job and keep that coveted number one rank. Most of the players I know that play pro badminton actually have post secondary degrees/certificates. They just won't take a job in their field until they are retired from badminton.
 My first coach used to tell me that badminton is a rich man's sport. And with the majority of high level juniors coming from expensive private clubs, his statement wasn't too far off the truth. These clubs have nice facilities, great coaches, and worlds of opportunities. The majority of the players that can afford the memberships of these private clubs often have more than enough finances to travel abroad to compete in most or all of the national circuit tournaments. Let me take now to say I have nothing against this way of life. Honestly if my parents had enough money to help me reach my dream without needing any extra finances, the only thing I would be doing would be training and competing. I don't have the motivation to go to post secondary now, but if I had that much money, I definitely would never find it.
 Let me tell you a bit about my mother. My mom was one of the top gymnasts in Canada when she was only 13. She trained forty hours a week and had little time for anything else. Her parents had four other children to worry about, but this did not make them stop supporting her dream. When their funds had finally dried up for good, my grandparents re-mortgaged their home, and made massive budget cuts so as to allow my mom to continue training and competing. Although my mother suffered a career ending injury just before her chance at Olympics, she has told me many times she would not have changed anything. The experiences she took away from that part of her life made her who she is today.
 I don't know when my personal funds will dry up, but I have already started trying to find new ways to fund myself. Our top Canadian men's doubles player has found a company and a product he is truly passionate about, and is using this to hopefully pay for his badminton. Most athlete funds in Canada are too busy looking for new Sidney Crosby's for their advertisements, so they can't be bothered to look at Alex Pang's or Adrian Liu's.
 So if you choose badminton as your career, you are basically committing financial suicide. But will you regret it?
If you truly love badminton, you probably won't.