That's nuts. I had to replace some old Cisco media players that we used as digital schedule boards outside of ~20 classrooms. The Cisco players were quite old and only needed to load a webpage that pulled schedule info from elsewhere and displayed it in the proper format.

I decided to do this with RPi and went through several revisions as I learned/relearned a lot about Linux. The first version was built on full Raspbian and added a basic server listening on some port or another so I could remotely reboot the things by clicking links on a simple website I put together. That build would usually crap out after a few months and the Pis would stop booting fully from the Sandisk MicroSD cards.

Most recent rev was built from the "Lite" version of Raspbian as I was looking to stay slim and have less stuff to update/run in the background/cause issues with the basic operation of a device that only needed to boot, load Chromium, and open a webpage defined in the startup script.

Those have been a lot more stable (no more reimaging a card here and there every month or two) but they still occasionally crap out and a reimage is the only option (maybe once every 6-8 months). This is in an air conditioned building with stable power, wired LAN connection, and fast SD cards. I can't imagine they would be even this reliable running all the time in any sort of "hostile" environment or even using wireless networking.

I looked into network boot but didn't really have the time or resources to set it all up on the school's network.

Is the OS perhaps booting in readonly mode? My experience with the first and second gen pi was of frequent data corruption. I have the later models, but i have hardly used them, so cant tell.