> Has the network centralized? By this metric yes by a lot.

Do you know what betweenness centrality is?

random_

Imagine I crated a huge huge number of nodes that do nothing. The number is so huge that my nodes that do nothing are 99% of nodes. So 99% of nodes do nothing and 1% of nodes handle all payments.

Has the network centralized? By this metric yes by a lot.

lightning

Payment Censorship in the Lightning Network Despite Encrypted Communication

Rsync25

I'm not sure that is a good measure

Imagine I crated a huge huge number of nodes that do nothing. The number is so huge that my nodes that do nothing are 99% of nodes. So 99% of nodes do nothing and 1% of nodes handle all payments. 

Has the network centralized? By this metric yes by a lot.