The article is actually incomplete. Some insider builds already lack the old taskbar, it can't be invoked and if an application relies on it you simply get a crash.

This is not new behavior from Windows. When legacy features are going to be removed, they do stagger updates when users have known software conflicts installed, they also might throw warnings. This is exactly what we are seeing now.

Though the fact this small article is just reporting on Reddit information rather than testing insider builds is not my fault nor my concern.