That's a legitimate strategy for some Amazon trinkets but CPUs are a major purchase for most people such that they won't likely let them sit in a closet beyond the warranty period.
Heck, even as a SWE building my own computers for almost 20 years, I still have no idea how to properly diagnose a hardware issue when it arises. Beyond checking for explicit errors in journals/logs, and the usual memtest/BIOS update/reinstall the OS from scratch, I resort to replacing each component one by one until the issue disappears. But it's time consuming, and sometimes quite costly. I suspect most people simply replace the entire thing if it's not a prebuilt PC still under warranty.