Awful movie and here is why

I guess you hated "Inglorious Bastards" as well...

Quentin is wanting you to languish in 60’s Hollywood and the day to day lives of the characters to set up the ending because it’s that way of life in Hollywood that’s preserved by the ending. Not only are the murders diverted saving lives and the careers of Dalton and a Booth but the Hollywood life as it was at that time is allowed to continue on. That entire vision of Hollywood that QT presents to the audience during the first 3/4 of the film is is essentially saved and is allowed to live on into the 70’s rather than taking a darker tone as we know it. Our heroes saved everyone at the Polanski / Tate house and Hollywood but who knows for how long. Hence Once Upon a Time in Hollywood.

SPOILERS
1. He did exactly what he wanted to do with it.
2. You're right in that it wasn't a "story". It was showing what it was like in Hollywood at the time with the presumption the audience member has knowledge of the Manson Family murders. These are just days in the lives of some Hollywood folks that (in real life) ended in brutal death. We know it, the characters don't. It was suspenseful and realistic in that Tate and friends had no idea how their day would end. But we did. Or thought we did, which is one of the reasons the ending is so satisfying. It's such a relief to see Tate saved as opposed to ripped to shreds. And justice being done to the killers.
3. This wasn't a traditional film. It allowed the audience to feel immersed in the Hollywood experience. Every scene was fascinating in one way or another. So much to take in if one is interested in character motivations, history, Westerns, behind the scenes stuff, cars, driving, Manson, justice, or if they're missing a culture of days gone by.
4. Everyone's different, but I didn't want it to end.

In your opinion it's an awful movie. Why do you think you are making a statement of fact? You are not. It's what you think, it's your opinion, that's all. You are entitled to it...but it carries no weight whatsoever, anymore than the opinions of those who liked it.

It didn't have much of a story intentionally. It's not that kind of movie. It's a character driven piece.

I didn't think it was too long. I enjoyed all the time spent with these characters.

Non sequitur! That is the set up to the joke

Some movies are more meditations than stories. This is one of them.

Could it have been trimmed a bit? Possibly. I thought a few scenes were too long or extraneous too, but on the balance I think QT got it right.

I would have like to see Sharon Tate's character get more development so that her survival provided more of a 'sense of relief' at the end.

You coudl say that a good part of pulp fiction was really about nothing as well but people loved It.