I will give you one. You want to embed the coreutils in some other projects ie. a browser. But at that point it's cheaper for you to submit your modification upstream because you are making money selling the browser not by selling modified coreutils. Maintaining your own fork is not worth it once you make meaningful changes.

I think this is the reason why uutils are being funded by Big Tech and why they chose this license. (to get funded) correction: I only found that they are funded by the Sovereign Tech Fund and apparently the author is open to changing the license, they don't care (see video/presentation).

But yes, I agree this whole comment section is deranged. The reason why Ubuntu chose uutils is because of Rust's safety and because of speed. In some workloads (I think it's sorting) they totally smash the GNU counterparts.

For Ubuntu it does not make any sense to make a proprietary fork. You don't choose your OS based on its coreutils. If they added a new convenience flag for their proprietary grep, it would just make them look bad. Also skilled users would hate it because now their scripts would not be portable. Or if it were really that big of a gamechanger, the feature would get added to the other coreutils and Ubuntu would end up with nothing but bad reputation. Unless they made change to the underlying code for performance. Then it would be harder to implement in the other coreutils but as I said before, nobody would care. Faster and safer coreutils are a nice to have, not something people base their OS choice on.

Edit: added source to author's stance on license