I think a lot of sufferers of it are psychosomatic. The demographic for long covid doesn't match the demographic of those who are most at risk of the virus or get the worst symptoms. Instead, it matches the demographic most likely to complain about symptoms from other diseases that have attracted large numbers of sufferers, only to have most of them disappear when the disease became less trendy: Fibromyalgia and gluten intolerance, who had massive spikes in patients claiming to have the diseases, and suddenly big drop offs, for lifelong illnesses that don't go away. These patients tended to be affluent, white, middle-age women, who are not remotely the most at risk from covid, but are disproportionate in claiming long covid.
The vaccine probably has a placebo effect on these kinds of folks. Underestimating the full power of psychosomatic driven symptoms is a big problem. The mind can really make the body sick, and there's a lot of science backing this up.
I should specify that i don't think this is voluntary, or humans wanting attention. I think it's induced by excessive fear-based media and the subconscious, combined with the huge evolutionary advantage of the mind having the ability to induce vomiting if other tribe members who have eaten contaminated food begin getting sick.
https://www.newscientist.com/article/dn23851-what-if-your-gl...