Why would they? The “old” tools work very well, are well known and are likely used in millions of scripts.
The new tools will have more bugs, unfamiliar options and unexpected behavior (due to them being new), and the improvements current “modern” alternatives bring to the table are often very minor.
It would be cool if the GNU project sponsored a new updated ‘standard’ set of tools though.
Why would they? The “old” tools work very well, are well known and are likely used in millions of scripts.
The new tools will have more bugs, unfamiliar options and unexpected behavior (due to them being new), and the improvements current “modern” alternatives bring to the table are often very minor.
I'd expect they'd 'adopt' the tools and redistribute them under the GPL, if they did.