But there is a steep gap in the spectrum at 16 on page 7

That's the spectrum of LoRAs, which are LoW RAnk by design.

Yes. But from their paper: “In our analysis, we present compelling empirical evidence for the existence of universal subspaces within LoRA adapters across different modalities and tasks.”

I also don’t understand what they write under figure 2, since resnet50 has 50 layers, not 31.