The champions you see on television and on magazine covers, as well as other highly-ranked, high-profile players usually have racket contracts. Some are actually paid to play with a particular brand while others get rackets free.
Often we watch a great point between two good players that is loaded with fantastic shotmaking. A beautful first serve somehow is blocked back with an incredible off-balance return. This followed by repeated, powerful forehand and backhand groundstrokes directed with uncanny accuracy all over the court. Wow! And just when we expect an inspired conclusion to this building crescendo...one player dumps an easy one directly into the net.
In the old days, wooden rackets warped; that's why they were stored in presses, screwed tightly onto the frame. Even so, wood fatigued and got softer with use. Any hard contact with the court produced an immediate crack which rendered the thing useless.
When you're tearing your hair out wondering why your game has gone sour, a knowledgeable, understanding coach can be invaluable. His or her experienced, trained eye sees things you may be missing out on the court.