Each vendor has to make their own decision on whether or not to attend York. The status of the pandemic in PA to include using/not using masks, and return on investment (how many people will actually show up for the effort/cost of attending). A smaller business would be greatly hurt if one of its employees contracted the virus, so I am sure that is the primary reason for not attending.
I am a TCA member and tired of being cooped up and not seeing train friends, and have my Oct 21-23 yellow pass. But reading this forum (not just this topic) and seeing how many here do not plan to wear a mask to keep the Delta variant in check bothers me enough that I am no longer going. I work with children so I am very cautious.
Maybe more vendors, who would be face-to-face with hundreds of folks every day, would have attended if they knew there would be a mask requirement and other controls in place. Guess we will never know.