Why don’t the default monitor profiles have a calibration expiry?

The default color profile used for each monitor is generated automatically based on the display EDID which is stored in a memory chip inside the monitor. The EDID only gives us a snapshot of the available colors the monitor was capable of displaying when it was manufactured, and does not contain much other information for color correction.

Getting a profile from the monitor vendor or creating a profile yourself would lead to more accurate color correction.