most importantly, because there is no need. the reward for mining via coinbase transaction is increasing with rising bitcoin value and will likely do so for considerable time. with a money supply inflation >1% for over a decade its not neccessary to maximize incentive through fees. its not productive to let a currency have 10% of the total money supply as yearly maintenance costs.
fees as extra incentive are a short-term non-issue. its much more important to optimize fees and block size for a well-running network and best user-experience.
Topic: Which Development Issue Is More Pressing? (Read 662 times)
Transaction fees per block have been rising with the transaction volume while the block size has remained below the maximum size
Well of course total fees per block has been increasing, that is to be expected because 1) there is the minimum fee per transaction (preventing relay spam) and 2) because of the uncertainty with what the "correct" fee is, senders err on the side of sending slightly more than needed rather than less.
the proposal for creating good financial incentives to replace the market lost when the size is uncapped
That's because it's a non-existent problem. Transaction fees per block have been rising with the transaction volume while the block size has remained below the maximum size, which is effectively the same as being uncapped. The idea that the supply of transaction processing capability must be capped below equilibrium in order to increase fee revenue is counter to the observable facts.
Even though non technical users have been moaning like there's no tomorrow regarding the "block size limit" endless controversy, the proposal for creating good financial incentives to replace the market lost when the size is uncapped got five times fewer views and ten times fewer replies than a scheme for voluntarily measuring taint of coins that requires no change in the protocol:
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