You can get a similar experience to the Fenix (but without the higher end sports features) with other Garmin sports watches. The Forerunner 255 is well reviewed and very similar to the Fenix for about half the price.
I wonder how changing the rating system in cases like these from a five star scale to a thumbs up/down system would affect user behavior and system usefulness. It seems like ebay, uber, airbnb, etc all suffer from the same "anything less than 5 stars is effectively negative" issue.
In US anyway, my understanding is that most of our containment structures should be sufficient to survive a plane impact without loss of containment. [1]
If you go on Oxygen, you basically want to have enough to get you down to camp. The effects of coming off Oxygen can be totally debilitating. There are also advantages to climbing without Oxygen if you have the proper physiology, mainly you don't have to worry about carrying g it or running out.
Anatoli Boukreev's book about the 1996 Everest disaster is very insightful. Among other factors climbers running out of Oxygen contributed to the scope of that disaster. It's a fascinating read.