I was somewhat attracted to the idea of buying a PS4 at the end of its life to reap the benefits of cheap-ish game ownership and play all the exclusives from its era.
This however, is one of the reasons DRM is the bane of ownership of a legitmately purchased game: You only own a copy until the publishers yank out your legally obtained license to own the software, which in this case, once the PSN is permanently offlined, your CMOS battery is the last line of proof of owning the licensed copy on the PS3. Once the battery dies, your copy will die with it as well.