I know they had accounted for the need to reboot the processor in the event of a radiation anomaly. I’m interested to know what real world data they’ve collected in the time the helicopter has been flying.

Probably still a "It Depends" answer? What do you want that CPU to do? Curiosity and Perseverance could last a long time and would a faster CPU enable significantly better science instruments? A rover might be able to travel farther autonomously, which is cool but it's a science mission, not a race course.

Why is this one lasting so long? Presumably we know the radiation conditions on the surface so testing more units in a lab is a better guide than one plucky helicopter.

It can, and that's big news. At the very worst you could get away with simpler CPUs and redundancy instead of massively costly and limited supply rad hardened chips.

They use a RAD hardened FPGA to handle the avionics. The Snapdragon is for the less critical activity.

It is still probably a good idea to have the main equipment running on radiation hardened hardware, while the more unimportant stuff runs on off the shelf components.

That way at least if something goes wrong with the non-rad-hardened equipment, it could be rebooted or debugged using equipment which is rad-hardened

I'm no scientist but that's my take on the matter.