The labeling and disclosure is pretty much solved. The killer and the cost monster is the handling. That's why you see that "Processed in a facility that also processes XYZ" label on some foods.

I had an old coworker with a severe milk protein allergy. So bad that he would get a reaction if he (lip) kissed his wife after she drank milk or had ice cream. So eating out was basically impossible, because his food would pretty much need to be made in a totally separate kitchen to avoid any contamination risk.

So we are right back at my point. Do we force every restaurant to have a secondary allergen free kitchen so my coworker can eat there? Or does my coworker just deal with it and stick to vegan places (like he did)?

If your point is that cost doesn't perfectly match frequency, sure, it was off the cuff, but it doesn't change the underlying nature of "accommodating everyone".