Ubuntu LTS has an additional 5 years of security support through Extended Security Maintenance thus giving LTS releases a full 10 year lifecycle. https://ubuntu.com/about/release-cycle
>ESM is available through an Ubuntu Advantage for Infrastructure subscription for physical servers, virtual machines, containers and desktops, and is free for personal use.
Note that if you click through "personal use" means "up to 3 machines" and obviously doesn't apply to infrastructure. RHEL has free "personal use" subscriptions too, except they apply to up to 16 machines.
And also:
> Initially, free subscription is available for Ubuntu 14.04 LTS only.
The fact is if someone wants to run a Linux host for 10 years with security patches they can with Ubuntu. They cannot with CentOS Stream. Yes, they could switch to RHEL and pay for security patches but RHEL is a different OS than CentOS Stream.
>ESM is available through an Ubuntu Advantage for Infrastructure subscription for physical servers, virtual machines, containers and desktops, and is free for personal use.
https://ubuntu.com/security/esm
Note that if you click through "personal use" means "up to 3 machines" and obviously doesn't apply to infrastructure. RHEL has free "personal use" subscriptions too, except they apply to up to 16 machines.
And also:
> Initially, free subscription is available for Ubuntu 14.04 LTS only.