One of the options, "encrypt to an ssh key" is an interesting convenience. Since most of us already have ssh keys deployed.
Parent's point still stands: PGP is a standard (with widespread adoption, mind you) whereas Age is not. Whether it is a good standard or not depends on how you're using it.
Can you explain why you think it isn't?
The sheer volume of gpg-signed apt/rpm/tar packages downloaded and verified everyday cast doubt on your claim.
I bet the number of packages downloaded for CI alone would invalidate this claim.
People use PGP because it is standard, widely-adopted, and does what people need it to do. From where I'm standing, people who argue against these three facts are underestimating PGP or overestimating their own favored solutions.
If you want to change our discussion to be about replacing PGP instead, then I completely agree that people should replace PGP with modern properly-standardized alternatives if such exist.
Here's what happens in the super-common, basic case of 'installing a third party (i.e. not from the distro repos) package on some debiansy Linux':
You access the the developer's webpage (via a browser and https) and read the installation instructions. They tell you to curl in (over https) some pgp key and some (https) endpoints for finding and downloading the package.
You apt-whatever and the package is installed.
The PGP part of this can be replaced with NOPs and this is no less secure. All the heavy lifting here is done elsewhere using infrastructure that actually has wide adoption and standardization and does useful things.
Email is hard to secure for obvious reasons. The PGP itself is fine, even though it could be updated.
* https://articles.59.ca/doku.php?id=pgpfan:index
It turned out that PGP is not all that bad...
Also, very few of these users actually use secure versions such as signal or wire. They all happily post on Facebook‘s messenger and WhatsApp and don’t care about crypto.
WhatsApp uses Signal Protocol, and protects many order of magnitude more messages every day --- or, if you like, bytes of plaintext --- than PGP ever has or will.
Email not being a messaging protocol is... a take.