Can you point out, at which point in time exactly, the public TLS PKI infrastructure has been reduced to WebPKI?

Can you point out at which point in time exactly it was designed to serve every use-case?

The public TLS PKI was never supposed to serve every use case and you know it. But let me point out when it was possible to get a public CA certificate for an XMPP server with SRVname and xmppAddr:

  Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 1096750 (0x10bc2e)
        Signature Algorithm: sha256WithRSAEncryption
        Issuer: C = IL, O = StartCom Ltd., OU = Secure Digital Certificate Signing, CN = StartCom Class 1 Primary Intermediate Server CA
        Validity
            Not Before: May 27 16:16:59 2015 GMT
            Not After : May 28 12:34:54 2016 GMT
        Subject: C = DE, CN = chat.yax.im, emailAddress = hostmaster@yax.im
        X509v3 extensions:
            X509v3 Subject Alternative Name: 
                DNS:chat.yax.im, DNS:yax.im, xmppAddr:chat.yax.im, dnsSRV:chat.yax.im, xmppAddr:yax.im, dnsSRV:yax.im

Ironically, this was the last server certificate I obtained pre-LetsEncrypt.

So you understand that there are different purposes as well. Are you saying that you can't get a client auth certificate any more?

Huh? The entire purpose of that EKU change was to disallow that usecase. How did that demonstrate problems for WebPKI?

This post here is the demonstration, that some non-WebPKI purpose is causing issues and complaints. This has happened before with SHA-1 deprecation. WebPKI does not want this burden and should not have this burden.

Ok, so this is an official split of "WebPKI" and "everything else PKI" then?

Last time I checked, Let's Encrypt was saying they provide free TLS certs, not free WebPKI certs. When did that change?

You are being pedantic but also pedantically incorrect.

Lets encrypt provides value by providing signed TLS certs that are enrolled in webPKI (i.e. trusted by browsers).

If they were just provided a (not necessarily trusted) tls cert, like what anyone can generate from the command line, nobody would use them.

Let's Encrypt also provides value by providing signed TLS certificates that are enrolled in all major operating systems, and that can be used to authenticate any TLS server.

This is a significant and important use case that's totally ignored by the "WebPKI" proponents, and there is no alternative infrastructure that would provide that value if WebPKI would e.g. decide to add certificate constraints limiting issued certificates to TCP/433.

That's being overly pedantic. PKIs for different purposes have been separate for a while, if not from the start. LE is still giving you a "TLS cert".

Great circular reasoning there buddy.