See all the company logos? Webpack is great for sure, but why does it attract so many sponsors? There's loads of other great projects not receiving a dime despite having Patreon pages or whatever.
It's the logos (and links) themselves! Because by putting my logo on your Github and project page, I can both mentally and practically claim it as a marketing expense. Marketing being an established bucket of money you can use for things that increase your company's visibility.
But if you simply offer a donation system, or feel-good sponsorship, how would I even classify that? Sounds complicated from a business point of view. Even a support contract is a harder sell than just pure marketing.
Heck, if I know my customers are using projects X and Y, I'm willing to pay just to put my logo in front of those users even if we as a company are not using X and Y ourselves! And by payment, I don't mean a $50 one-time donation, companies are willing to pay $X00-$X0000 per month for that kind of targeted exposure. And if you do this for your project, please note that companies value direct links to their chosen landing page much more than to some generic "sponsorship aggregator" page for the company.