Did you play Final Fantasy XV? That game planned DLC from the start. It impacted the game heavily. Some of the DLC never even got made.
They said it wasn’t planned for XVI because it wasn’t planned at the time. But also to let people know that the base game wouldn’t have pieces missing from it. It’s truly a completely standalone experience and I believe that DLC was only an afterthought at that time.
But also, companies say all the time that they’re open to stuff, DLC, ports, sequels but nothing is planned yet. It’s really common. Sometimes they go do those things, sometimes they don’t. That’s what “not planned” means.