An instance can do whatever it wants, within the terms of the license of the software it runs.
But so can every other one. And ad drive social media has demonstrated itself to be toxic social media. So, you'll end up with a lot of other sites defederating from it.
Being ad driven is what has led to Reddit doing what it's doing, after all. The people who have come here from there should be much more concerned about emulating that kind of model all over again. Otherwise, why not just stay there?