I don't think we have to worry very much about the story being rushed.
Yu Suzuki's Red Bull interview:
“I’m afraid that the story will not be concluded with Shenmue 3,” Suzuki says, frankly. “After thinking it through, we decided that forcing a conclusion in Shenmue 3 would only make the story feel rushed and compromise the game as a whole.
I'm trying to find the quote, but I think Yu did say III would finish Chapter 5 and go beyond Chapter 6, so let's assume it gets partway into Chapter 7 the same way II got partway into III. That seems reasonable.
Anyway, the developer/publisher list for PSX has been announced and there's no sign of YSnet. The list may be for exhibitors, i.e games the public can play at the event, so there's still every chance Shenmue III will be at the stage show.