I believe that the tendencies toward introversion and extraversion are inborn. But like many innate traits, their expression is influenced by environment. A born introvert, for example, may have to act like an extravert because of his job, the friends he has made, or some other social aspect of his life.
But lockdowns have allowed tens of millions of persons to work at home rather than in an office. And lockdowns have greatly altered socialization: no dining out, no social gatherings, no church-going, etc.
Such changes, I suspect, have caused many millions of suppressed introverts to discover that they are happier than they were before the lockdowns began. Work is less draining because it is less “close up and personal”. The absence of socialization comes as a surprising relief — no more anxiety about what others might do or say that requires a response or comment; no more anxiety about participating in events the one doesn’t really enjoy.
Not all reborn introverts will continue to enjoy their new freedom, of course. But many of them will do more of their work (perhaps all of it) from home if they are given the option of doing so. And many of them will allow some social “obligations” to lapse, and feel good about it.
So lockdowns have a liberating aspect. Who knew?