Hard disagree with the notion that S4 is less likely that S3.
When S3 came about the series was completely dead. There was no real way of quantifiably gauging demand for the title prior to the Kickstarter, there was no clear image of what a resurrected Shenmue game would actually look like and, even if the first two issues could somehow be overcome, there was no team in place to make the game.
Fast forward six years, however, and there’s now a blueprint in place for what Shenmue 4 will/could look like and a pre-assembled team of people who already have experience making a Shenmue game. The sales of Shenmue 3 and the success of the game’s Kickstarter offer a pretty clear indication of the potential demand for a fourth title and the impending anime and slow trickle of sales of the first three games provide hope that that number could easily increase between now and the game’s eventual release.
Shenmue 4 is by no means a certainty, but I think a fourth game is far more likely than the third ever was and by using some of the existing assets and ideas from its predecessor, would also be a lot easier to make. That Yu and Cedric are trying to secure a larger budget is undoubtedly slowing things down, but were they ever to switch to pitching a “bare minimum” S4, I suspect they’d secure funding almost instantly.