People can certainly make vast changes. The rituals of Marine Corps boot camp are great example of a large change taken on by thousands. Walking through the Hiroshima Piece Memorial museum also causes deep change on every soul that enters. FIAT propaganda has changed entire countries in to slave states.
Change is the only thing constant in our lives. The that you are hitting on, is the fact that people don’t consciously realize their ability to control their change, change others, or be changed.