That's part of it but as they made more adult focused games, it drew a lot broader range of consumers to gaming which changed the stigma surrounding gaming being a kid's hobby which in turn drew in even more consumers.
yes, which had little to do with Sony, the gaming market was already moving in that direction in the early 90s with violent games aimed at teens/young adults like Mortal Kombat & Doom becoming big hits.
you are giving Sony credit for something that was already happening before they even got into the game. games aimed at this age group were releasing more frequently in the years leading up to PS1 and would have continued to increase in quantity & popularity with or without Sony.
When the herd loses its way, the shepard must kill the bull that leads them astray.