This to. It's not good for a dogs health to have to hold it that long. I assume he has to sleep at some point to, so she's not getting let out then either, unless he has some piss filled puppy pad situation going on nobody is allowed to see. My dog had a UTI once (she hated rain when she was younger and would just stay in all afternoon when it was pouring) so I get up and make sure she goes out every couple hours.
I also just let her wander around when I'm home during the day, it doesn't hurt my feelings if she wants to go take a nap in another room for a while, then again I don't need my pet to be on camera as a prop for my job.
And safe spot training isn't supposed to be needed for more than a bit, that's for one you need them to chill TF out for a few minutes while you're coming in and out with groceries or getting something out of the oven.