It was also planned to upgrade the block size by satoshi but since he disappeared it never happened.
The networks need to have separate fates. BitDNS users might be completely liberal about adding any large data features since relatively few domain registrars are needed, while Bitcoin users might get increasingly tyrannical about limiting the size of the chain so it's easy for lots of users and small devices.
I think in that last sentence, Satoshi correctly predicted that the max block size may never be increased. And I think the Bitcoin community will go that route, and if they will ever increase something, then it will be the max witness size, not the max block size. Also, you can see that the max witness size is just a parameter you can change in your node, everything is prepared for changing that, little tweaks here and there will do the trick, if the community will ever decide to do that.