After that event, the royal family struck a deal that gave the extremists more influence in exchange for holding onto power...we're talking women banned from television, cinemas shut down, extreme gender segregation, etc. It was that way until MBS, a relatively liberal person, ascended and whisked some power away from the religious police and extremists, with an iron fist, of course.
Despite their vast oil wealth, Saudi really lacks the human capital to keep the gears going without the help of foreign expats. If the oil wells hypothetically dry up tomorrow...the country is in deep trouble.