  The Bitcoin Lightning Network (LN) is designed to improve the scalability of
blockchain systems by using off-chain payment paths to settle transactions in a
faster, cheaper, and more private manner. This work aims to empirically study
LN's fee revenue for network participants. Under realistic assumptions on
payment amounts, routing algorithms and traffic distribution, we analyze the
economic returns of the network's largest routing nodes which currently hold
the network together, and assess whether the centralizing tendency is
incentive-compatible from an economic viewpoint. Moreover, since recent
literature has proved that participation is economically irrational for the
majority of large nodes, we evaluate the long-term impact on the network
topology when participants start behaving rationally.
