I want to agree with him, but money shows he's wrong. People will go see sequels, adaptations, and remakes. Studios will not stop printing money because Spielberg wants to take the high road. Fortunately, studios will keep making Spielberg movies, but up and coming filmmakers won't have his pull.

What Spielberg might want to do is, create a fellowship for creatives, and see if he can get some of his pull applied to their works. He might have to put up some of his own money, like as an investor hoping to make a return. I think that's kind of what a production company (i.e. Amblin Entertainment, here) does, but I'm not 100% sure.

Also, we shouldn't be so quick to forget that Spielberg bought up the rights to Ready Player One so he could change it into an advertisement for his own movies. He did keep the spirit of the movie, and the movie was awesome, but everything was changed to advertise his previous films. The movie still worked — it was a fun homage to the 1980s — but it was never meant to be a showcase of one person's work, it was meant to be a showcase of the 1980s and the culture Ernest Cline grew up in, as a whole.