Because whereas you've worked with 4 PT offices that you've seen what your are seeing, I've worked, volunteered, and done my internships for undergraduate at more than 24 locations, and these other members on the opposing side of your thoughts have worked at many more as well. All of which if anyone stayed late, it was actually the PTA's more so than the PTs. At some of my clinics, if you stayed late you got paid for those hours or some clinics will schedule you an extra hour where you have a clear in the schedule for possible last minute inserts where everyone gets their notes finished. For PT's and PTA's at all my sites, they filled out the same paperwork. Only difference is the PT would review the PTA's notes to make sure they were done correct (easy 10-20 minute process depending on how many PTAs you have, which was still on the clock)and obviously do things like evals which are done during the hour of evaluation. I have worked in multiple states from Ohio, Florida, New Jersey, Pennsylvania, Massachusetts, Indiana, Tennessee, and Kentucky, whereas it seems that you have solely been located in one general vicinity being a part of California. Like said before, the different settings have different paperwork. How many patients you have during one hour can vary greatly among settings, if you only have one patients an hour and work per day 9-5 , you can have 7 patients at MOST in a day. If you're in a sports PT facility, you can see 3 patients per hour instead of the 1. So your facility matters on your notes. When you have more patients an hour, you typically have your PTAS do all the work after evaluations and the work you wish to do, some patients you may want to work more 1-on-1 with than others who know what they are doing and have been there for a while. That means you have that entire time to personally evaluate your patients and do their notes while the PTAs are focused watching the patients to make sure how their form is on movements and helping them in their next exercises. PT's on average from my personal experience have more time to do notes than PTAS. PTs have always left on time at my clinics, with the exception of a few times they would leave 30 minutes later than they liked because hey got caught up in conversation. I always stay with the PTAs and would often get out 3-4 hours later than PTs at some locations. So you say there are no good reasons, but everyone has worked in different settings, in different places, and the majority have had experiences that oppose that of yours.
As for time for your health, one location had a garden outside the office, they were the fittest people I've ever met. They got to the office at 8am, worked out for 45 minutes, took a shower (sometimes not), and would start work at 9am. You are at a gym if you work in the right setting. I had another outpatient setting and an inpatient setting where there was a gym affiliated with the center, meaning free gym membership right next door. You can go in an hour early, or an hour late. 18 of my locations had full sized kitchens to cook healthy meals
During the hour break, or you could meal prep meals for a week if there are no local healthy places to eat. Then there are those that got more days off than they wanted working for their company because there is a set amount of hours one can work in a week. They would be told they HAD to go on vacation days if they worked too much in one week (they never were unpaid off the clock.) I would say 85% of PTAs when asked why they aren't PTs stated they couldn't do 3 years of school, they didn't want to pay that much at the time (many which regret it now), or that they didn't get into PT school so they applied for PTA. It's rare to find someone that wants to do PTA but not PT, because most PTAs realize they are more overworked than the PTs and for the price they are charged. I don't want to sound rude, but it is sounding more like your clinics are the "exception to the rule" than all of ours. Try getting out there more and learning a little more, ultimately it's your choice, but there's ways to make what you want to work as a PT, you just have to do your research and find the right places. And maybe it won't be where you want to live, but sacrifices might have to be made to get the hours you want. Best of luck!