What do you mean by this? If 2mb of transaction data is generated every 10 minutes, but only 1mb of it is mined, what is the free market solution?
If the goal is to have bitcoin be an actual working currency for the people (and it may not be that to you), then it would seem the goal should be to be able to process the vast majority of transactions, instead of just those for the richest half.
A "solution" that is economic and solved by free markets tends to be about how to distrubute limited resources. I.e. here's a nice piece of property for sale - who gets it? The highest bidder. problem solved.
But I don't think the challenge for bitcoin is how to auction off space in the blockchain, it's how to make that space wide enough to be reliable as a potential currency for common people. If, every time you bought a candy bar at walgreens, you had to pay for the candy bar and take a guess at an extra fee for your payment and hope it goes through 10 minutes later... it just would not work.
So the market would be solving something, but it wouldn't be towards the goal of bitcoin being a currency. And honestly I think that's what the opponents of the block size increase want. As cryptocurrency tech evolves, we're seeing that various parties have new self interests to promote. Competing technologies, etc. And they benefit by bitcoin becoming artificially limited. I know there are other reasons, but it's a big part of why this is even a debate.