Ornamentation makes perfect sense as long as it consumes rare resources. When you can find enough resources to build expensive ornamentation in good times, you

Ornamentation makes perfect sense as long as it consumes rare resources. When you can find enough resources to build expensive ornamentation in good times, you can probably survive hard times decently well, only your ornamentation will suffer. But when you use all the resources that you can get for breeding as much as possible in good times, the population will probably collapse in bad times.