I happen to believe you have to be realistic about improvements in technology and can't realistically assert that nothing is "decentralized" unless it works over, say, dialup (or ham radio).
It is a fact that five years ago there were very few >10 mbit connections outside data centers. Now they are commonplace and inexpensive in many (not all) locations, and 100 megabit connections are becoming common too.
^ this is exactly the reason for all the work on our ledger, which I hope to release some information on this coming week following from consensus.
Its pointless to have a decentralized network where to be of any use, everyone needs to have access to the best of the best....it should really be able to operate in the worst of the worst if possible and the most basic tasks should be possible with no perceivable deterioration.