I think there is some musing in there, but not so artfully concealed or communicated. The DiCaprio storyline touches on the usual Hollywood mid-career existential crisis and it seemed to suggest that Tarantino might actually have something to say. The other two "characters", if you can call them that, are there just to show us more of the world.
But what little substance was there, perhaps more-so in earlier drafts, is buried by the kid in Tarantino who just loves how cool hippies, Westerns and the 60s were. So the whole thing just comes across as a thinly veiled excuse to showboat production values and Tarantino geekdom. And I could live with that, if it all was just tighter in structure and rhythm. But it isn't, so sorry, "Hollywood love letter" is not good enough a pitch to sell me on this.