The two curves start together. At low numbers — 5, 10, 20 Fellows — both lines rise, because small groups work. Everyone can find everyone. No tools are needed.
The amber curve is realisable value without tools. It peaks modestly near Dunbar's 150, then falls away. Beyond that limit, adding more Fellows adds density but destroys accessibility. By 1,000 Fellows, unaided value has collapsed to near zero.
The fuchsia curve is RSA Connect. At heuristic strength zero, it is identical to amber — because without tools there is no difference. But the two controls are coupled: as you raise heuristic strength, adding more Fellows now increases value instead of destroying it. Every new Fellow is another node the heuristic layer can route through, another source of knowledge the system can surface. Density times heuristic intelligence equals growing value. The same density that killed the amber curve feeds the fuchsia one.