I said built into the design - there's a difference. Same with power, voltage, thermal cycling. All are a range of values built into the design. keep all the variables within design parameters and the IC will have same life expectancy.
You said "built into the design of any IC".
In any event, a LOT of IC-based circuits have ZERO temp limiting or control, and even those that DO have it often do not enable it by default or set the default to a rather high temperature.