Katharina and Miguel (and a few others) "get it" – sharing equipment amongst a small group can very easily lead to efficiencies. You can use these efficiencies to carry less, to extend your comfort, or safety margins. Mountaineers, explorers, hunters, military personnel, and other people who work in the wilderness have understood this since the beginning of time.
A prime example is first aid – a group of three or four can actually carry an injured hiker over substantial distances to safety, execute crevasse rescue, sustain CPR etc.; whereas a solo or duo probably could not, even with special gear. I say this as a guy who has had to carry wounded off a battlefield, and who twisted my ankle so badly I broke the tip of my fibula.
I do not take issue with people who chose to go solo for whatever reason. But many of the responses to this thread follow a pattern of excuses to justify a personal preference, rather than reasonable arguments about what could be reasonable achieved by pooling resources. If you are cutting toothbrushes to save grams, then potentially sharing a stove between two people rather than carrying two stoves represents tangible weight savings, and these savings can easily scale upwards in technical or more extreme conditions.
A sensible precaution against people not bringing equipment, or not having things in a proper state of repair is running through the checklist and doing a "function check" at the trail head. You can personally bring everything you normally would, and adjust your load as necessary to cover shortfalls.