I don't understand why this would be called "rotting". Sure, it's old, but it's actively maintained by its original author, a Gmbh has been established around its maintenance and it retains a few developers for the purpose.
We do not call the Linux operating system rotting, which is a project in a similar position to gpg, nor do we call the git project rotting. All of these are old C code bases but are actively maintained. They are in c, but they've squashed a lifetime's worth of bugs. Git is notoriously bad on the command line to use, but we still use both gpg and git because they're both useful and super stable. Calling something rotting just because it's not written in Rust ignores the years and years that their maintainers have put into it.
This is to say nothing of geopolitics. It's difficult for Europe to trust anything made in America. It was for this reason that Richard Stallman encouraged Germans to make encryption software, the import of which America allowed but the import of American encryption software in the Germany was illegal. This is why Werner Koch started gpg. Sequoia seems to be made by a foundation based in America. I doubt a significant following in Europe will pick it up.
Too often this sensitive topic is ignored, particularly with regard to encryption. Just recently gitea was taken over by an American corporation. The project was soft forked because the community was outraged. But they didn't change the license to AGPL, they just maintain the soft fork under a European company. The problem clearly isn't the license then, it's the country of origin. And that's just for source control.
Using the original gpg is a great way to show more international unity, but we all know that's a secondary reason to use software. The primary reason is that it's a quality piece of work that will be very difficult to reproduce.