Word of caution folks: the anime will no doubt be even more niche than the games. The closest analogue I can think of is Xenosaga, another game series I love. Like Shenmue it was an overreaching disappointment of a game series that had to be cut short, but it also received a 12 part anime series based on the first game.
I doubt this series will set the world alight, but it'll hopefully be a nice addition for us fans.
I dont think we need to worry about anything. It sounds like the whole project was started by a Shenmue fan
who luckily has the power and ressources to do something like this.
The project started after Shenmue 3 was released. So this anime doesnt really surf on a hype wave or anything.
Which means they wanted to do it either way, not because they hope they can gain or earn anything.
I dont see this project as a problem or risk or anything.
The game companies like Shibuya and Deep Silver are not involved in this project.
Its not being made just to push the game series, its being made because the Adult Swim guy wanted to do it.
In the best case scenario, the Shenmue anime pushes the interest for the whole IP into a postive direction
but even in the worst case scenario i doubt that the game publishers / distributors or whatever are leaving the ship
just because some Adult Swim anime got bad reviews or something like that.
I see it more as "free content" for fans.
Just because the anime reviews are good or bad it doesnt mean that Shenmues 4 budget depend on that.
No one is gonna throw 50 Mil USD at the game just because the anime was popular.