Why do photographers have to spend three generations in poverty?

This is not true. Just poor for three generations.

But learning photography is a very expensive hobby.

First, you bought a SLR with a head. A few months later, you want to buy a telephoto lens. After a while, you want to buy a wide-angle lens and a fixed-focus lens. Then you think that all the dog heads I bought should be replaced with cow heads, filters, polarizers, tripods, monopods and camera bags. Then you think this is a C-frame SLR and should be replaced by a full-frame SLR.

Then I used Canon series first, and then I took a fancy to Nikon series. Ok, change the doors, all of them.

Endless.