Why do artist's change their style as they move through their career?

the sculpture i am pretty sure you are talking about is the statue b. the david statue now lives in the galleria dell'accademia, florence, italy. it was made by ‎michelangelo.

name the above painting and its artist. how has the artist used balance, variety, and movement in this piece to emphasize the man waving the cloth, in the upper right-hand corner? be specific in your response.