Makes sense and gives a compelling reason for regular reboots.

This is also true because of fileless malware. Not all malware attempts to write to the disk because it leaves behind artifacts that could get captured or detected. Depending on what the attacker goals are, they may prefer to have the malware simply disappear if memory gets reset.

Or like you wrote it is possible they just didn’t bother implementing a survival strategy because most people don’t reboot their phones very often.