That sounds nice in theory, but if I'm running a business, unless I have more money than I know what to do with, I can only donate so much to open source development. Let's say my entire application is written using Vue.js. In that case, regardless of how many little utility libraries I use, I want to make sure that the vast majority of my contribution goes to the Vue.js contributors because Vue has, by far, the most significant impact on my business, and I'd like to make sure I can continue to depend on it in the foreseeable future. In contrast, that utility that title-cases strings that I use all over the place is great, but I wouldn't be heartbroken if it didn't exist anymore.
> If dependency X is a pithy trivial thing that doesn't deserve your funds, and you care so much, then write your own into a utils file. The reality is, you didn't and you're using someone else's work.
If the author of the utility felt that way, they could have given it a commercial license and sold it to me. I know this makes me sound cold, but open source authors know the deal they're getting, and nobody should expect to get paid any significant amount for their contributions. From a business perspective, it makes sense to fund anything you would be in real trouble without, because your money increases the odds that those projects continue to grow and be improved/maintained.
Having said all of that, I still find StackAid to be a great idea, and if I owned a (profitable) business, I could see myself using it in addition to larger donations to specific projects that my business depends on. That would be a great way to distribute the funds to all of the projects I use while still focusing on a small handful of key pieces of software.