Yes, they do. The GPL’s copyleft clause requires companies to release the source code of any modifications they distribute, ensuring contributions back to the community. The MIT license, however, allows proprietary forks without this obligation. In other terms, the MIT license is effectively permitting companies to “jump out” of the open-source ecosystem they make use of.
As far as I’m aware, contributions from major corporations to GNU Core Utilities specifically (e.g. sed, awk, ls) have been limited. Most development has historically come from the GNU community and individual contributors. For example, UTF-8 support was likely added through community efforts rather than corporate involvement. However, as these corporations increasingly back projects moving away from GNU and the GPL, their intent to leverage the permissive nature of the MIT license becomes evident. Should ‘uutils’ gain widespread adoption, it would inevitably lead to a significant shift in governance.