It doesn’t take 6-8 hours to play how you want. More like 1 hour. I think you’re misunderstanding what’s being put out there. You don’t have to finish a 6-8 hour campaign to unlock choosing your path - you’re doing that from the first hour onward. The game gradually introduces you to the Shared World, giving you time to play how you want, letting you spend time in each season before you are in a fully synchronized world where everyone is in the same season.
The first 10 minutes is a lot like the e3 demo, then you arrive at the Festival and start your first summer. A quick tour of all four seasons.
Then you enter the “Horizon Life Prologue” where you get to spend time in a full Horizon year doing what you want, progressing based on what kinds of things you like to do. Sure there’s some hand-holding here, but it opens up very quickly.
At about 1 hour, once you finish your first prologue Autumn event, the Drivatars in your freeroam world are replaced with real players and you have online modes available. Or you can play Solo if that’s your thing. The players you see in the world with you are at the same point in their Horizon Life as you, same season. But you can do whatever you want.
At around 4-5 hours, depending on how you play, you qualify for the Horizon Roster, your second summer, and earn your first Wristband. You enter a fully synchronized world where each season lasts a week. How fast you get there depends on how much “influence” you earn (think of it like XP). You get Influence for racing, stunting, creating and sharing content, streaming - whatever. You’re doing all that from hour 1 onward.