Because the one who stands at the top doesn't do it for the money of course.
I feel like you just threw a shitload of creative people in Hollywood under the bus there to make starwars look better. Believe it or not some people actually enjoy making things, ever notice all the unpaid art/media in existence.
It just so happens that you need money for freedom in this world. So yeah if money is required to keep doing what you love then people are going to want it.
Some directors don't give a shit about making an extra buck and just want to put their vision onto the big screen no matter what.