22 points
The five year policy is for ChromeOS, not ChromiumOS. ChromiumOS-based devices may have more or less support.
15 points
1 point
ChromeOS and ChromiumOS are Linux.
The problem with ChromeOS (and Android) devices is that hardware support is usually only available in a fork of Linux which gets as little maintenance as possible for the five years. You end up with the choice of running and old kernel that supports the hardware but not some new software, a new kernel that supports new software but the hardware doesn’t work right, or taking over maintenance of the fork yourself. The same problem occurs with uncommon hardware on non-ChromeOS devices.