Not necessarily. On the PCB there is a controller whose contacts eventually come loose and that is the fault here. The OP says he and his wife are both heavy users of their respective phones, which could indicate that the phones go through a lot of contraction - and expansion - cycles due to heating up and cooling down, thus likely hastening the process of those contacts coming loose. A user who doesn't use their phone that much also won't see the issue that quickly.
I've experienced similar issues myself several times, like e.g. the tablet I have got replaced by the manufacturer after its WiFi-chipset lost contacts due to the tablet heating; the tablet had worked great for half a year or so, but I got the Android-version of X-Com and played it quite a lot, then during the middle of one play-session the tablet lost WiFi-connection. After rebooting the tablet WiFi was gone, the system couldn't find WiFi-hardware at all. And these old laptops I have: one of them had a loose connection to the display and one of them had the connections from the GPU to the PCB loose -- both fixed with a bit of a heat-gun applied at the right spot to reflow the solder.