Microsoft monitored the computers of the Windows Insider group and found that computer crashes were greater than 99% crash free with certain parameters.
None of us have the data.
Microsoft chose CPU, BIOS settings, Drive partition configurations, TPM, etc. so that there would be major improvements in performance and security.
For end uses that have unsupported hardware / firmware etc. they have the option to upgrade or clean install in the unsupported fashion.
There are multiple websites that have reported the successful upgrade of computers with very old hardware.
These include desktops, laptops, and tablets.
In order to upgrade in the unsupported fashion the websites reported registry and file modifications so that the Windows update agent was not able to recognize the unsupported parameters.
Most computers can clean install Windows 11 in the unsupported fashion.
Computers that upgrade or clean install fashion may not benefit from the improvements in performance or security.
Also end users with unsupported upgrades or clean installs may have later problems updating Windows or updating Microsoft Defender.
End users must evaluate the risks and benefits.