If routers become cheaper and smarter the network will grow, you might get more direct routes (less hops), or simply better load balancing (based on latency and-or throughput, maybe even indicated by the size of the flow, so your SSH session will be low latency low jitter but also if you start to download a file via a subchannel it might get shifted to different routers), and with better balancing flows will get distributed not just considering packet drops, but maybe cache hits too (latency basically).

Anyhow, upkeep costs are very important, because they limit the size and efficiency of the network. (High barriers to entry limit growth, high upkeep encourages centralization, which is bad from a reliability and fault tolerance aspect.)