You can click through to see specific incident summaries. It looks like a significant amount (if not majority) of events are inflight on passenger flights (as opposed to on the ground, tarmac, ground handling, or freight operations). There were 85 total incidents in 2024 (there were some 9 million passenger revenue departures to give another sense of scale).
Lost phone is a problem because:
* Could be in a place that increases risk of thermal run away to begin with - classic example would be caught in the seat hinge. But even being stuck surrounding by cushioning could increase the risk of overheating
* Decreased visibility. The faster you can react (ie, try to dump the thing into a thermal protection bag / get it away from other flammables) the better. If you read the incidents, you'll see time after time the sequence "passenger notified flight attendant, who then placed it in a thermal containment bag, flight completed normally".
I could see changes to rules that will begin to prohibit storing batteries in overhead compartments (which aside from the pinch problem, actually has all the same risks of losing a phone). Or perhaps mandatory/routine pre-emptive use of thermal containment bags.
The airliners know there's no going back. They must accommodate for batteries, so they'll seek the right balance.