Head too far down this path of thought and you hit an existential crisis pretty quick though: "why are you storing photos?" "who will look at them?" "will anyone be looking at them in 200 years? 100? 50? 10?"
On a long enough timescale we all die and are probably forgotten. I've actually spent a decent amount of time resisting the urge to just delete all my old photos (I have things going back to early high school - taken on a Sony Mavica that used floppy disks).
There's a very liberating feeling to the idea of just having no history at all - probably similar to the appeal of the idea of having all your works crumble to dust when you die, which is also something I've seen people refer to at different times.
But, since I haven't done that yet, and since managing an on-site server or disks is it's own stress (i.e. eventually my house will burn down or flood and I'll lose everything...so what was the point?), then paying that $x/month is basically the price I pay to defer having to really think about it.