That is one reason why serious HODL people keep studying everything they can about each holding, not to trade, but to sell when disaster is imminent. Over the years I've sold several before the keenly developed disdain for the obvious set in to the overall market.
Examples: Xerox, Polaroid, Eastman Kodak. All three had huge competitive advantage in technology, all three tried to protect their turf rather than continue innovating.
Today we have Tesla, BioNTech and some others which have had great success and continue innovation as quickly as they can. Those two both have seen large share price drops because the 'analysts' think the 'big guys' will come and eat them up.
The moral is, if we see Tesla stop or slow innovation it is time to sell. Until and unless that happens JODL works well because the markets have no awareness or concern about sustainable advantages.
That is why they all missed the coming disaster of Kodak, Polaroid and Xerox. After all they were invincible.