They say the block size should be kept low so that transaction fees can increase for the future when no block rewards will be available.
But if the block size is increased then there will be more transactions to provide fees.
So it is not necessary that the block size should be small for more fees.
This is a common misconception. It's like saying that if we sell 1000 apples for $1 today, then we can sell 8000 apples for $1 tomorrow. It's economics 101, supply and demand. You increase the supply, you don't get more demand, you get lower prices instead.
In our case, let's assume we will have 100 MB blocks tomorrow. Why would you pay a fee? Fees would be 0.
Actually we are all assuming that demand will increase. I.e. demand for those blocks will increase. We are talking about the future, not about tomorrow.
Miners have to ask themselves: What will bring about greater revenue in the future; smaller blocks with higher fees or bigger blocks with lower fees?
I vote for bigger blocks because I think the blockchain should be for as many people as possible. It shouldn't just be for the elite.
Smaller blocks is a case of elitism.
