Whenever someone creates a "better and lightweight" successor to latex they will over time be asked to, or by themselves need to add another small feature to extend its capabilities will over time move closer and closer to the LaTex features set.

Or someone will use it and create a large document and find that Typst just does not have enough features they need, they will get frustrated and feel the need to move over to Latex.

Just like the original markup definition was fine, but then we have a forrest over forks or similar projects that add specific features someone needed.

That said if your needs are covered by Typst it's certainly easier to learn.

Are you implying latex is a global optimum?