Better Capacity with More Nodes
The number of nodes in the P2P network is unrelated to scalability. Due to the entire validating network operating in lock step, they all do identical work independent of their peers no matter how many of them exist in the system. One node, a thousand nodes, a million nodes all operate at the same effective speed (and the limits of the network are the same). Adding more peers actually worsens the load somewhat, as you increase the total bandwidth necessary to get the transactional data to everybody in the network quickly.