The real question is why miners aren't mining these transactions to get to the limit. Why are they issuing empty blocks, why don't they even care to change the 750kb parameter to 1mb etc etc. The obvious answer is because the fee incentives are too low, so why should they?
The obvious answer is because the lionshare of their income still comes from the block subsidy. That subsidy has to drop first. Which will happen in due time. Only then empty blocks will not be mined anymore.