Actually it wasn't a joke. But sort of a dream baked into a joke
I totally agree with you.
And I'd like to add that a prequel would be the absolute best way to return to the world of Shenmue 1 in a new package. I have, for a while, been thinking about how the story could play out in Shenmue 0:
Ryo would still be going to school, where his relationship with Nozomi was better. At this time, before Iwao's death. We would see a different Ryo. Not as stuck in the future, not full of questions and anger. This Ryo is a little happier, more in the present moment. We can maybe see how Ryo and Tom met for the first time - and how Ryo got along with his other friends.
But there would be other problems. Maybe some gang, thugs and maybe even something that is related to the Chi You Men but not directly.
Ryo would wake up in the same room as in Sh 1, go to school and spend some time there. A little bit like Persona 5, but different.
Here Ryo have the same Yokosuka, Dobuita, Harbour and so forth but everything is slightly different.
The movie theatre, that were under some building work in Shenmue 1 could be open and functional in Shenmue 0.
My idea is that either Ryo fight the bad guys in there, or maybe Ryo goes there with Nozomi to watch a movie when suddenly there's a fire and smoke start to spread out, because of a thug taking revenge on Ryo for beating his thug friends ass.
Or something better then that! -But something that explains why it's closed and under re-construction in Shemmue 1.
In this Shenmue 0 world, you could actually visit Nozomi's house and spend time with her, in a similar way you do with Shenhua in Sh III. As you could not do that in the original Shenmue 1. I always thought when playing the original ´Where does Nozomi live and why can't I visit her?´, such a wasted opportunity in my opinion. We all love Nozomi. I would love to know more about her.
We could get to know Iwao more, what his personality was like, and to see how he raised Ryo into the person he is "today".
We could experience more funny/stupid momets with Fuku-san. Who knows, maybe Fuku-san got that Pig Money Box from Ine-san on his birthday just to learn how to save money.
In my opinion, this is the absolute only way for Ryo to "return to japan" because I think he won't do that in Shenmue IV or V.
This is all just me dreaming again. But if this was possible, if SEGA could make a prequel, having YS's right to use the Shenmue III model for Ryo and some other assets, then this prequel could possibly lay ground for a remake of Shenmue 1 and even
2.
I know this is nearly impossible but I love these kind of ideas.