Innovation can be achieved by mature, large companies, not only by startups.
While most innovation comes from startup companies, some of the top innovative companies are mature and large. (Apple was founded in 1976 and generates $228 billion. Google: 1998, $78 billion, Microsoft: 1975, $87 billion.) The myth acts as a self-fulfilling prophecy and deters large companies from attempting to innovate like startups.