Regarding Guillermo-Gate, I've seen people use it as a reason to boycott OSS projects.
Going after OSS projects that are openly governed isn't going to do what you want it to. Vercel makes its money from its hosting platform and paid products. OSS is not a paid product and while contributes goodwill doesn't directly impact the bottomline. And these project's reach well exceed Vercel.
First the list is longer than you think. Yes Next, Svelte/SvelteKit, Webpack, SWC, TurboRepo. There are also Nuxt, Nitro, React. Seb, the current visionary of the React team, as well as Andrew work at Vercel, not Meta. Should we boycott React metaframeworks too? Remix/RR, Tanstack React? Good luck finding projects that haven't received money from Vercel in the past.
Secondly impact. When you realize things Nitro/UnJS that exist to keep the platform open and not locked in to a single deployment platform, and are used outside of Vercel (Tanstack Start, SolidStart, Analog). Or Webpack/SWR which power countless projects it is difficult to make this about Vercel.
Third, I've seen the suggestion that Vercel acquires OSS the way one does companies. It doesn't work like that. The way you kill off OSS is easy. Remove their source of funding. NuxtLabs could have gone under and took Nuxt with it. I've seen this happen to other projects.
More so because these are open projects, it isn't like you buy their customers. You can still deploy Nuxt/SvelteKit anywhere. It creates good will, but they can go anywhere. There are no contracts. NuxtLabs was a company, but Nuxt isn't. These are more like charity foundations.