Another reason is nowadays with all the variety of dietary restrictions in vogue, it’s much harder for a host to prepare a meal everyone can share. Potlucks or a bland collection of help-yourself dishes (which often are nothing more than an odd collection of appetizers) is standard fare.

I’m fortunate to have friends in their 60s and 70s where I can still enjoy the traditional dinner experience.

I wouldn't call diagnosing people for actual medical issues we learned about since the 70s an en vogue thing. Other than those, it's pretty much just vegan / non-vegan.