If the percentage is taken only by authors to focus on programmers then it is denied to the account of marketing and writers and the whole system can fall.
The funding system should not be viewed as focusing on programmers. It MAY provide funding for programmers, but it can also provide funding for marketing or even authors (the latter would require either an automated off-chain distribution process or a further hard fork to allow funding proposals to pay into the social reward pool, but both are absolutely feasible).
The proper way to view this (funding system) is as an alternate method of voting for rewards that is structurally better suited to potentially larger and/or longer-lived projects than 7 day post payouts.
I realize this is somewhat radical but my own opinion is that 100% of the social reward pool (author+curator) should go into the funding system first, and then stakeholders can vote how much of the inflation budget goes to these forms of marketing (which is what they are) as opposed to other forms of marketing and/or other uses of the budget (such as blockchain development).
RE: Pros and cons of two versions of Steem Proposal System