How would you plan to measure decentralization?
I don't. But when i show following hypothetical scenario
1. 6 years ago you moderate VPS or PC to run full node
2. Today you can run full node with Raspberry Pi 4
Some people would agree that cost of running full node (excluding storage size and IBD) is cheaper today and could improve decentralization.
Even if two participants of the Bitcoin protocol appear as different nodes, they might have an out-of-band connection and be ran by the same person.
I agree, but it's out of scope from my question.
What about bandwidth? I believe Bitcoin’s bandwidth needs, as a decentralized network, is very underestimated. Rate of growth for bandwidth is slow, and network latency slower, which means that block propagation speeds might not scale at the same rate if average bandwidth among nodes increases.