If the miners still control which transactions to include in blocks than ultimately they decide upon the limit. Is your concern more to deal with the miners and you prefer the developers to impose restrictions upon the market to remove the ability for miners to process more transactions?
The problem here is that Bitcoin is designed in such a way that there is no counterparty to miners when it comes to transmission and storage costs, so it seems impossible to add a truly free-market price discovery mechanism.
So there are 2 other options: impose a hard limit by protocol rules or change the rules to alter financial incentives somehow so it's not profitable for miners to generate big blocks.
This could be done if the prices remained stable (see my previous idea, for example), but unfortunately Bitcoin price relative to everything else is externality, which cannot be accounted for by the protocol rules alone. And since no free-market solution seems to be available, the problem seems to be impossible to solve efficiently right now.
Increasing the block limit is simply kicking the can down the road and buying some time to figure out what to do.
(I am for it, by the way).