As much as I agree with the sentiment behind this post, I disagree with the implementation. The nature of open source code is collaboration. Paying for collaboration seems like it would hinder progress altogether and possibly direct the project into a direction that is not suitable for the poor majority not paying. One more thing that bothers me is that money for maintenance should not come from developers. This is like robbing Peter to pay Paul.
Disclaimer: I am the CEO of Code Sponsor (https://codesponsor.io)
Code Sponsor is trying to help provide those who are maintaining OSS projects with untethered sponsorship funds. They can go about doing their business on the projects and be making money through sponsor-based ad revenue. This provides them with the incentive and finances to justify continued support on those projects that end up being abandoned when unfunded.
I agree that this is a HUGE problem that needs to be addressed. Code Sponsor's approach is to go where money can scale: marketing budgets.