1) Individual developers and the companies that want to sponsor projects will otherwise just continue to talk past each other. The developers ask "Why aren't companies donating?" while the very use of the word donation is already a complete showstopper for a company that otherwise doesn't flinch at dropping $50K on a one-day booth at a developer conference that draws maybe 15K visitors at best (a website like Material UI or Webpack probably does 10x that in a month, a perfect fit!). If GitHub doesn't set the system in place, large players like Webpack will continue to "get it" (they offer invoices for sponsors!) while Bob with his 5K stars project will be left out.

2) If the attribution is on a case-per-case basis, companies will continue to select just a few big showcase projects. If the handling is uniform it would be much easier for companies to do things like spreading their spend out all over some segments like "top-100 Go projects" or "libraries built on top of D3" or whatever audience they'd like to target.

3) If there is actually significant uptake in a project, meaning more than a handful of sponsors, it quickly becomes a serious timesink for developers just to track who is active which month at which tier, which sponsors churned etc. and then to actually attribute everything correctly. How about, sponsor picks the project, developer does nothing except gets paid, and all campaign links, logos etc. automatically taken care of. Hmm, I guess what I'm describing is sort of like an AdWords for GitHub now that I think of it :)

Heck, I've sponsored a number of projects back then as a teenager with a fledgling Internet business - with the express purpose of advertising to highly technical users I wanted to potentially sell to.

I'm not sure if it was terribly effective at sales marketing, but it was highly effective at marketing towards the types of employees I wanted to work with. I see sponsoring open source projects as more of a recruitment thing than sales thing these days.