perhaps you can tell me in what manner you think LN contributes to decentralization. The way I see it, it will inevitably end up a hub/spoke system - meaning more centralization. Also with node and path discovery being mediated by (other?) centralized actors.
I agree, although I think it's not the correct to say that the overall network topology will be be more centralised, just that one task the network performs will be divided into 2 layers (the miners on one layer finalising tx's, lightning hubs one layer below setting all the transactions up). And it's pretty much true that miners and exchanges could easily become the dominant players in lightning hubs, but it can't stay that way forever, because neither exchanges or miners will be around in large numbers 20 years from now.
tl;dr all Lightning does is split the transaction market up, not much point complaining that the same big Bitcoin companies will get all the business, because they do already now.