1) most restaurants in US and high-end Europe that survive and thrive do so by having big margins on alcohol. Their margins are not single-digits. (edit: just saw other comments mentioning this).
2) Many restaurateurs don't have the skill or knowledge to run a restaurant, and yet they do so because it's often one of the few options left (if you can't land a high-paying job, and don't like a low-pay one).
3) What she describes in the article is very US-centric. Most of Europe, or Japan (where I am currently sheltering before returning to the US soon), have a very different restaurant landscape. Most are small mom-and-pop shop, they have very low ops costs, and can do not too bad in a time like this one. I spoke with a few owners recently (in Italy and Japan) and they all confirmed it. They mostly don't have personnel, or if they do, their relationship is flexible enough that they can quickly react to 2-3 months of 50-70% less business than usual.
4) For the long term, nobody knows what's going to happen. Are we ever going back to pre-covid levels? Don't know. Probably not. Some restaurants will close, sure, as well as car dealers, etc. Good restaurateurs will manage to find a way, IMHO.