Toyotaro is set to make an original manga.

[Vegeta th3 4th]

If this one shot becomes a long running series, then the chances of Toyotaro returning to Dragon Ball will be slim to none. It was announced as a one shot, but a lot of manga, including Naruto, One Piece, and even Dragon Ball, all began as one shots.

[Hellspawn28]

I think Toyotaro doing his own thing is good because he can't just live off of Dragon Ball forever. Plus, we need some money to keep him living. That DBS money is going to run dry at some point.

[Desassina]

Sounds like any fan's path when contributing to an official series before departing to create his own:

1. Taxman and Stealth contributed with Sonic CD, 1 and 2 remasters before creating Mania, and then they moved on to their project (Penny's Big Breakaway).
2. Toyotaro contributed with the movies and series' retelling before creating his own arcs and now he's moving on to his own project.

[JulieYBM]

Yeah, working with another's work is a pretty good way to build skills. After a while, it helps you learn how to break down storytelling and from there you can begin to think about how to create your own original series while having some practice prior that you can learn your mistakes from. While I absolutely advocate for freeing artists from illectual property and a world where we need to sell our art to survive, I think it's definitely a useful tool to have to know how to work on a project based on a prior work.