Insects love electronics, with the heat and noise they generate. And when electronics sit in storage for a long time, the critters can crawl in from neighboring items.
This is just as likely to happen with a non-ISP router.
Ok, in all fairness I don’t have any stats to back up that claim. But nobody else does either.
That open source router you love so much may have been sitting in storage even longer.
I have mixed feelings about ISP routers, and ISPs in general.
But insect infestation is a serious issue in consumer electronics and has nothing to do with ISPs.