Poor science i'm afraid, it's the endothelial cells that are effected by viral infection, epithelial is the skin.
Flu causes inflammation in the endothelial cells, as does the common cold. Flu however can be extremely damaging as it provokes a body wide inflammatory response, many people are left with permanent damage from flu infections.
Covid is a respiratory infection, like flu, and triggers a similar response in the immune system - the only marked difference is that covid is far more infectious, resulting in people getting it again and again in short order, whereas most people only get influenza a few times in their life.
If influenza was as infectious as covid you would see a similar pattern of long term sufferers.
This doesn't diminish the scale of the very real problem it is going to be causing - at least for our lifetimes, if it does attenuate, which it might still do future generations may not be so hard hit, but likely many of those who have long covid will suffer for the rest of their lives, which is a grim proposition.