Okay, so, I watched a video that really helped put things in perspective. I know the guy will be some youtuber you've likely never seen before, but what he has to say is pretty legit and help clears up a lot of the misinformation being spread by gaming sites asserting that Sony is funding this project.
The tl;dw is that basically, Sony has only agreed to pay the marketing costs for Shenmue 3, and it is maybe verified that they're paying the cost to have the game ported from PC to PS4. Sony has not actually agreed to fund development, which has been verified by the guy running the project as a whole who said in an interview to expect the majority of the funding to come from the Kickstarter campaign. Granted, Sony doing the marketing for the game is no small thing. That is a huge chunk of change that doesn't have to come out of Kickstarter funds to get the game recognized and out there. It still means that what you see at the end of the Kickstarter is in all likelihood what you can expect from the final product. If a stretch goal isn't hit, extra Sony funding isn't going to get it in the game. If there isn't enough money for a big world with lots to do from Kickstarter money, there won't be a big world with lots to do when the game releases.
Unlike with other major Kickstarter campaigns for games as of late, this one seems to have already made the best deal they could see themselves getting from anybody and are otherwise entirely reliant on the fans to get the funds to make the game. With that said, if you want Shenmue 3, if you want it really badly, consider tossing in that extra $10 or $20 instead of base cost for a digital copy. It won't be the game some of you have been waiting 14 years for if you aren't willing to toss in the money to make it happen.
Edit: Granted, I will give you all this -
It would be difficult to craft a Shenmue game that doesn't even have 1/10th of the budget of the inflated original cost to make the first two games. Especially with game development costs only going up, not down, it seems safe to think that even if another major publisher isn't on board for funding the project yet, they may very well be. In the end, Sony is just doing marketing and PS4 porting. I could see another publisher being able to make a deal, but it seems far less likely that Sony will simply say "yeah, I don't mind if someone else hops in and starts taking profits". At the same time, it may have to happen if Sony doesn't intend on contributing funding towards actual development, which at this point in time, we have no reason to believe they are.