Very often, the desire to change arises from experiencing major pain (of which trauma is one kind).

But this is not always the case. The impetus for change spans the spectrum of human emotions including dissatisfaction, pleasure seeking, existentialist realizations and envy/peer influence.

Trauma is definitely not a pre-requisite for change. It may be the most observable external cause to the effect, but that doesn't mean it is more useful than the rest.

The people I know who reinvent themselves the most are those driven by joie de vivre and a sense of self-expression.