My answer is that whatever transactions the miners choose to include in the blocks have sufficient utility to be included.
This should follow real supply and demand for block space, not an arbitrary blocksize limit. The blocksize limit should be continued to be used as an anti spam measure which should exist significantly above the current average transaction volume.
So if I decide that my posts should be included on the blockchain, and a miner decides that a few Satoshi will reward hie enough to include them in a number of blocks, then that will be of benefit to Bitcoin. Even though every node will have to store them forever.
Yes, its the minner who risking real Bitcoins because of the orphan risks, so miners have incentive to act economically and not grow the blocksizes too much unless it is worth it.
Nodes have to download the block and process it, but its up to you if you want store all blocks for new nodes, and in future even if you store only random 1% of all blocks and there are thousands of nodes, the full blockchain can be downloaded by new nodes without a problem anyway - like torrents work.
It is better when miners and market decide the blocksizes than having centralized planned decision (basically another FED ? - wait, much worse because coders deciding now, not economy specialists).