Most fleet dashcams solve one problem well: they record. Nobody watches that footage live, so its value only shows up after an incident - as evidence for a claim, or as a clip someone reviews once a complaint comes in. By then, the accident has already happened, the near-miss already nearly wasn't.
The footage itself often doesn't help as much as it should. If a driver or a local operator can delete or edit a clip, an insurer or a court has every reason to question it - and a fleet owner has no real way to prove otherwise. Evidence that can be tampered with isn't evidence.
And there's a cost most buyers don't see coming: continuous recording from multiple cameras generates enormous amounts of video, and pushing all of it over a rural or patchy mobile network is either impossibly slow or impossibly expensive. Most of that footage is never watched by anyone - it just sits there, consuming bandwidth and storage for events that never happened.