This is a very good question that is not so straightforward to answer. A recent article in The Atlantic does a good job:
Sort of… This JAMA article does a good job describing the advantages of face shields: https://jamanetwork.com/journals/jama/fullarticle/2765525
But the exact question of simple mask + faceshield compared head-to-head with N95 alone, I don’t know if anyone has a definitive answer.
Ideally, it would be moot because everyone would have access to N95s and faceshields. When caring for COVID patients, I wear N95 + safety glasses + faceshield.
When I wrote “non-healthcare settings” I was assuming a setting in which the main risks are droplet and contact (both of which a faceshield does a great job blocking) and that there are not a lot of aerosols being generated. A primary advantage of N95 compared to simple mask is aerosol protection. But the N95 depends on a tight seal to provide that protection. Many of the N95s worn out in public are non-fit-tested, and — given the shortage of N95s — also from a subprime manufacturer (e.g. not 3M). In my experience, these masks don’t make a very good seal.
Responding to the OP regrets about nitrile gloves: You can make a box of 100 last a long time if you reuse them. When you take off a pair, turn them inside out and save them in a paper bag. Periodically let a batch of used gloves sit for a week or two in the paper bag and in that time any virus on them will have died and they can be reused. Just make sure you save them in a warm, dry place so they dry out.
Gently blowing into the glove will flip the fingertips right-side-out and make them easier to re-don. Reusing gloves in this way can also largely obviate the need for hand sanitizer.
If you don’t have access to a NIOSH-rated respirator, your best option to protect both yourself and others may be a simple cloth mask + plastic faceshield (assuming you don’t mind going out in public wearing a faceshield).
In non-healthcare settings, this combo may even be more protective than wearing an N95 FFR alone.
Setting aside the patient privacy concerns for a moment, I agree that more vivid imagery is needed. The early videos from the Italian hospitals showing wards full of helmet CPAP were a wake-up for me before my own hospital became a COVID hotspot.
Along similar lines, the impact on youngish/healthy people has been downplayed. Sure, elderly are hit the hardest, so the percentages of young/healthy deaths seem small in comparison. But by raw numbers, a lot of young people have been badly affected. Many of my sickest patients were in their 30s and 40s and had no serious medical problems before getting COVID.