I own/operate a flight school with a testing center. I've been with three different companies because of all the mergers.
Each merger or software change is somehow worse than the one before it. We used to be able to help applicants schedule and open slots day of or whenever they wanted. Applicants could cancel/reschedule without a penalty (if we approved it, which most of the time we did), now that is gone. Scheduling is all done through their awful interface and as a center we are not given any training on so we can't even help confused applicants through the process. The books are pretty expensive and you have to have as many copies of each as you do computers for testing (3 in our case, the minimum) so you're spending many hundreds every time there is an update. I can make a maximum of $66 (3 computers) for 3.5 hours of a proctors time.. under $19/hr and that's if all the stations are in use at $22 per test. Not to mention I pay for the computers, the internet, the heating/cooling (and PSI will write you up if an applicant complains about the temperature...), the scratch paper, the pencils.... you get the idea. It simply isn't worth it.
The upside in my case is that with the change there is another local place that can give FAA tests. They don't seem to do them often but they do show up every couple weeks. So I've decided that our testing center will only be opened when one of our students needs an exam. I used to accommodate the general public (drones mostly) but I can't afford to give exams at this rate so it's a choice I've made. I've already gotten a lot of angry phone calls about how someone needs to take an exam in the next couple days but there's nothing I can do, PSI made their choice. It's unfortunately at the cost of the applicants, not of the testing providers. I expect many places will follow.