If you like this sort of thing, perhaps you'll enjoy my SSL/TLS and PKI history where I track a variety of ecosystem events starting with the creation of SSL in 1994: https://www.feistyduck.com/ssl-tls-and-pki-history/

The short lived certificates started making a lot more sense to me when I discovered I could get Let's Encrypt to issue IP address certs. Clearly, in this context of use we need our certificates to die quickly.

You can now make any web server operate with a publicly valid TLS certificate without paying any money, registering a domain, configuring DNS or disclosing any personally identifiable information. It can be entirely automatic and zero configuration. The only additional service required is something like a STUN server so the public IP can be discovered and updated over time.

I feel this is a perfect complement to the current 1. link: https://satproto.org/ which implements its own CA system with different trade-offs.