The free market provides a solution. When the block size fills up, people will pay higher transaction fees to get their transactions through. Free riders paying zero or low transaction fees won't get their transactions processed.
The block size can only be increased if the big miners agree, and it's not in their interest to increase it.
It is clearly in miners best interest to increase maximum block size
but it is not in their best interest to produce larger blocks with the slow block propagation speed on the Bitcoin network as it stands today. I don't know who the idiot was that suggested as max block size --> infinity, tx fees --> 0. That simplistic view is complicated enough to make people think they are understanding some deep truth and react religiously as opposed to thoughtfully.
Peter Todd had a great and very simple write up on the calculus of tx inclusion On the dev list about 1.5 years ago or so. Max block size is not the problem at the moment
the very high
BTC25 block reward is the reason miners won't make large blocks. Block size will grow as block reward goes down and/or block propagation speed goes up.