the only thing that changed is what we call it, pluto has existed since before humans and will continue to exist after humans most likely, and it does not give even the tiniest shit about what we call it.

"planet" is an arbitrary category that mostly just exists because we like to put things into categories, much like the concept of a continent.

It's just really difficult to say that pluto is a planet if we want to have any sort of vague definition for what a planet is, because pluto is more similar to a ton of objects in the solar system than it is to the other bodies we very confidently refer to as planets.

If nothing else you have to also call ceres a planet if you include pluto, and how many people give a shit about ceres?