The increased update timelines by Google, Samsung and others roughly coincided with EU legislation coming into effect that mandates 5 years of updates after end of sales. We'll see.

https://www.heise.de/en/news/From-June-20-EU-gives-smartphon...

Correction: if the manufacturer chooses to provide updates, and they don't have to, they must continue to make those updates available for five years after end of sales.

In other words, manufacturers aren't required to publish updates at all, but if they do provide updates they have to make them available to users for five years after they stop sales. This only stops the case where a manufacturer ships a device and publishes updates for the device, but then takes those updates offline after they stop selling the device (but before 5 years is up).

https://www.theandroidportal.com/motorola-android-update-loo...