You're right, Google released their vision in 2023, here is what it says regarding lifespan:

a reduction of TLS server authentication subscriber certificate maximum validity from 398 days to 90 days. Reducing certificate lifetime encourages automation and the adoption of practices that will drive the ecosystem away from baroque, time-consuming, and error-prone issuance processes. These changes will allow for faster adoption of emerging security capabilities and best practices, and promote the agility required to transition the ecosystem to quantum-resistant algorithms quickly. Decreasing certificate lifetime will also reduce ecosystem reliance on “broken” revocation checking solutions that cannot fail-closed and, in turn, offer incomplete protection. Additionally, shorter-lived certificates will decrease the impact of unexpected Certificate Transparency Log disqualifications.

The background is that certificate revocation is a broken system and having short lived certificates makes the problem go away. You don't need to worry about how to tell people that some certificate is bad if it's only valid for a few days.

Ideally, certificates would only be valid for a few days, it should be automated anyway. This has other downsides as I can imagine, like creation of more traffic. My self signed CA for my home LAN has 4 days as standard, and it works perfectly fine.