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.

As the EDID cannot be updated, it has no expiry date.

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