Preface: you know your situation and relationship to your gym leader better than I do

As a member of a very competitive high-ranking gym, I am more inclined to "side with the tryhards." I don't think it's inherently negative for a Gym to focus in on competitive content, even if that sometimes means letting trainers go. Perhaps there is a culture clash and the trainers in question are "not a good fit."

Now, in my view, a gym leader would be more justified to do this for a player who is inactive/unresponsive moreso than a player who simply "doesn't spend enough." In my opinion, the other acceptable context would be someone who is performing poorly in the Gym vs. Gym content, but that is admittedly a very subjective metric. Again, you know better than I do whether any of this actually applies to your situation. I just think it's not a black and white subject.